### 3.2.1. CFX-Solver Output File

The CFX-Solver Output file is a formatted text file generated by the CFX-Solver and contains information about your CFX model setup, the state of the solution during execution of the CFX-Solver, and analysis statistics for the particular run. This is the same information written to the text output window of the CFX-Solver Manager. For details, see Text Output Window.

The file is formatted and divided into sections to enable quick and easy interpretation. The sections that are present for any calculation may depend upon which physical models are being used (that is, whether the model is transient or steady-state) and whether the CFX-Solver is being run as several parallel processes or as a single process.

The CFX-Solver will generate an output file with a name based on the CFX-Solver input file. For example, running the CFX-Solver using the input file named `file.def` in a clean working directory will generate an output file named `file_001.out`.

#### 3.2.1.1. Header

The header is written at the start of every CFX-Solver Output file and contains information regarding the command that started the job. This information is used to check which files were used to start the run.

#### 3.2.1.2. CFX Command Language for the Run

The CFX Command Language section describes the problem definition, including domain specification, boundary conditions, meshing parameters and solver control.

The section for the command file looks similar to the following:

     +--------------------------------------------------------------------+
     |                                                                    |
     |                    CFX Command Language for Run                    |
     |                                                                    |
     +--------------------------------------------------------------------+

     LIBRARY:
       MATERIAL: Water
         Material Description = Water (liquid)
         Material Group = Water Data, Constant Property Liquids
         Option = Pure Substance
         Thermodynamic State = Liquid
         PROPERTIES:
           Option = General Material
           EQUATION OF STATE:
             Density = 997.0 [kg m^-3]
             Molar Mass = 18.02 [kg kmol^-1]
             Option = Value
           END
           SPECIFIC HEAT CAPACITY:
             Option = Value
             Specific Heat Capacity = 4181.7 [J kg^-1 K^-1]
             Specific Heat Type = Constant Pressure
           END
           REFERENCE STATE:
             Option = Specified Point
             Reference Pressure = 1 [atm]
             Reference Specific Enthalpy = 0.0 [J/kg]
             Reference Specific Entropy = 0.0 [J/kg/K]
             Reference Temperature = 25 [C]
           END
           DYNAMIC VISCOSITY:
             Dynamic Viscosity = 8.899E-4 [kg m^-1 s^-1]
             Option = Value
           END
           THERMAL CONDUCTIVITY:
             Option = Value
             Thermal Conductivity = 0.6069 [W m^-1 K^-1]
           END
           ABSORPTION COEFFICIENT:
             Absorption Coefficient = 1.0 [m^-1]
             Option = Value
           END
           SCATTERING COEFFICIENT:
             Option = Value
             Scattering Coefficient = 0.0 [m^-1]
           END
           REFRACTIVE INDEX:
             Option = Value
             Refractive Index = 1.0 [m m^-1]
           END
           THERMAL EXPANSIVITY:
             Option = Value
             Thermal Expansivity = 2.57E-04 [K^-1]
           END
         END
       END
     END
     FLOW: Flow Analysis 1
       SOLUTION UNITS:
         Angle Units = [rad]
         Length Units = [m]
         Mass Units = [kg]
         Solid Angle Units = [sr]
         Temperature Units = [K]
         Time Units = [s]
       END
       ANALYSIS TYPE:
         Option = Steady State
         EXTERNAL SOLVER COUPLING:
           Option = None
         END
       END
       DOMAIN: Default Domain
         Coord Frame = Coord 0
         Domain Type = Fluid
         Location = B1.P3
         BOUNDARY: Default Domain Default
           Boundary Type = WALL
           Location = F1.B1.P3,F2.B1.P3,F4.B1.P3,F5.B1.P3,F6.B1.P3,F8.B1.P3
           BOUNDARY CONDITIONS:
             HEAT TRANSFER:
               Option = Adiabatic
             END
             MASS AND MOMENTUM:
               Option = No Slip Wall
             END
             WALL ROUGHNESS:
               Option = Smooth Wall
             END
           END
         END
         BOUNDARY: in1
           Boundary Type = INLET
           Location = in1
           BOUNDARY CONDITIONS:
             FLOW REGIME:
               Option = Subsonic
             END
             HEAT TRANSFER:
               Option = Static Temperature
               Static Temperature = 315 [K]
             END
             MASS AND MOMENTUM:
               Normal Speed = 2 [m s^-1]
               Option = Normal Speed
             END
             TURBULENCE:
               Option = Medium Intensity and Eddy Viscosity Ratio
             END
           END
         END
         BOUNDARY: in2
           Boundary Type = INLET
           Location = in2
           BOUNDARY CONDITIONS:
             FLOW REGIME:
               Option = Subsonic
             END
             HEAT TRANSFER:
               Option = Static Temperature
               Static Temperature = 285 [K]
             END
             MASS AND MOMENTUM:
               Normal Speed = 2 [m s^-1]
               Option = Normal Speed
             END
             TURBULENCE:
               Option = Medium Intensity and Eddy Viscosity Ratio
             END
           END
         END
         BOUNDARY: out
           Boundary Type = OUTLET
           Location = out
           BOUNDARY CONDITIONS:
             FLOW REGIME:
               Option = Subsonic
             END
             MASS AND MOMENTUM:
               Option = Average Static Pressure
               Pressure Profile Blend = 0.05
               Relative Pressure = 0 [Pa]
             END
             PRESSURE AVERAGING:
               Option = Average Over Whole Outlet
             END
           END
         END
         DOMAIN MODELS:
           BUOYANCY MODEL:
             Option = Non Buoyant
           END
           DOMAIN MOTION:
             Option = Stationary
           END
           MESH DEFORMATION:
             Option = None
           END
           REFERENCE PRESSURE:
             Reference Pressure = 1 [atm]
           END
         END
         FLUID DEFINITION: Water
           Material = Water
           Option = Material Library
           MORPHOLOGY:
             Option = Continuous Fluid
           END
         END
         FLUID MODELS:
           COMBUSTION MODEL:
             Option = None
           END
           HEAT TRANSFER MODEL:
             Option = Thermal Energy
           END
           THERMAL RADIATION MODEL:
             Option = None
           END
           TURBULENCE MODEL:
             Option = k epsilon
           END
           TURBULENT WALL FUNCTIONS:
             Option = Scalable
           END
         END
       END
       OUTPUT CONTROL:
         RESULTS:
           File Compression Level = Default
           Option = Standard
         END
       END
       SOLVER CONTROL:
         Turbulence Numerics = First Order
         ADVECTION SCHEME:
           Option = Upwind
         END
         CONVERGENCE CONTROL:
           Maximum Number of Iterations = 100
           Minimum Number of Iterations = 1
           Physical Timescale = 2 [s]
           Timescale Control = Physical Timescale
         END
         CONVERGENCE CRITERIA:
           Residual Target = 1.E-4
           Residual Type = RMS
         END
         DYNAMIC MODEL CONTROL:
           Global Dynamic Model Control = On
         END
       END
     END
     COMMAND FILE:
       Version = 12.0.1
       Results Version = 12.0
     END
     SIMULATION CONTROL:
       EXECUTION CONTROL:
         INTERPOLATOR STEP CONTROL:
           Runtime Priority = Standard
           EXECUTABLE SELECTION:
             Double Precision = Off
           END
         END
         PARALLEL HOST LIBRARY:
           HOST DEFINITION: computer123
             Host Architecture String = winnt-amd64
             Installation Root = D:\Program Files\ANSYS Inc\v%v\CFX
           END
         END
         PARTITIONER STEP CONTROL:
           Multidomain Option = Independent Partitioning
           Runtime Priority = Standard
           EXECUTABLE SELECTION:
             Use Large Problem Partitioner = Off
           END
           PARTITIONING TYPE:
             MeTiS Type = k-way
             Option = MeTiS
             Partition Size Rule = Automatic
           END
         END
         RUN DEFINITION:
           Run Mode = Full
           Solver Input File = \
             D:\examples\StaticMixer.def
         END
         SOLVER STEP CONTROL:
           Runtime Priority = Standard
           EXECUTABLE SELECTION:
             Double Precision = Off
           END
           PARALLEL ENVIRONMENT:
             Number of Processes = 1
             Start Method = Serial
           END
         END
       END
     END

#### 3.2.1.3. Job Information at Start of Run

This section describes the job characteristics in terms of the Run mode (sequential or parallel), the machine on which the job was started, and the time and date of the start of the run.

The section for job information for a serial run looks similar to the following:

     +--------------------------------------------------------------------+
     |                  Job Information at Start of Run                   |
     +--------------------------------------------------------------------+

     Run mode:       serial run

     Host computer:  host1 (PID:29363)

     Job started:    Fri Nov 29 17:01:29 2013

#### 3.2.1.4. Memory Allocated for the Run

Note: Allocated storage generally exceeds the required storage. 1 word is usually 4 bytes, 1 Mword = 1000000 words, and 1 Mbyte = 1048576 bytes.

The section for memory usage looks similar to the following:

     +--------------------------------------------------------------------+
     |        Memory Allocated for Run  (Actual usage may be less)        |
     +--------------------------------------------------------------------+
     |         | Real       | Integer    | Character |  Logical | Double  |
     ----------+------------+------------+-----------+----------+----------
     | Mwords  | 8.69       | 2.01       | 3.70      | 0.12     | 0.09    |
     | Mbytes  | 33.13      | 7.67       | 3.53      | 0.46     | 0.69    |
     ----------+------------+------------+-----------+----------+----------

#### 3.2.1.5. Mesh Statistics

Mesh statistics summarize the following domain-specific and global (across all domains) items:

- Mesh quality diagnostics

- The total number of nodes, elements and boundary faces in the mesh

- The area fractions of mesh interfaces that were unmapped.

Mesh quality diagnostics include measures of mesh orthogonality, expansion and aspect ratio (see Mesh Issues). For each measure, there are value ranges that are considered good, acceptable, and poor (the latter indicating potential accuracy or convergence problems). These ranges are annotated with OK, ok, and !, respectively, in the mesh diagnostics summary. The relevant minimum or maximum value is presented for each measure, plus a summary of the percent of the mesh with values in each of the good, acceptable, and poor ranges. Note that these percentages are rounded to the nearest integer value. In the sample output presented below, the worst expansion factor is 37, which is considered poor (that is, annotated with !). While slightly more than 1% of the impeller mesh exhibits similarly poor values, less than 1% of the global mesh is considered poor and “<1” is written in the summary.

The section for mesh statistics looks similar to the following:

     +--------------------------------------------------------------------+
     |                          Mesh Statistics                           |
     +--------------------------------------------------------------------+
     | Domain Name          | Orthog. Angle | Exp. Factor  | Aspect Ratio |
     +----------------------+---------------+--------------+--------------+
     |                      | Minimum [deg] |   Maximum    |    Maximum   |
     +----------------------+---------------+--------------+--------------+
     | impeller             |       34.7 ok |        37  ! |        13 OK |
     | tank                 |       61.4 OK |        11 ok |       303 OK |
     | Global               |       34.7 ok |        37  ! |       303 OK |
     +----------------------+---------------+--------------+--------------+
     |                      |  %!  %ok  %OK | %!  %ok  %OK | %!  %ok  %OK |
     +----------------------+---------------+--------------+--------------+
     | impe                 |   0   11   89 |  1   32   67 |  0    0  100 |
     | tank                 |   0    0  100 |  0    2   98 |  0    3   97 |
     | Global               |   0    3   97 | <1   11   89 |  0    2   98 |
     +----------------------+---------------+--------------+--------------+

     Domain Name : impeller

         Total Number of Nodes                                =        1710

         Total Number of Elements                             =        7554
             Total Number of Tetrahedrons                     =        7206
             Total Number of Prisms                           =         238
             Total Number of Pyramids                         =         110

         Total Number of Faces                                =        1494

     Domain Name : tank

         Total Number of Nodes                                =        4558

         Total Number of Elements                             =        3610
             Total Number of Hexahedrons                      =        3610

         Total Number of Faces                                =        2212

     Global Statistics :

         Global Number of Nodes                               =        6268

         Global Number of Elements                            =       11164
             Total Number of Tetrahedrons                     =        7206
             Total Number of Prisms                           =         238
             Total Number of Hexahedrons                      =        3610
             Total Number of Pyramids                         =         110

         Global Number of Faces                               =        3706

     Domain Interface Name : ImpellerPeriodic

         Non-overlap area fraction on side 1                  =    0.00E+00
         Non-overlap area fraction on side 2                  =    0.00E+00

     Domain Interface Name : TankPeriodic1 TankPeriodic2

         Non-overlap area fraction on side 1                  =    0.00E+00
         Non-overlap area fraction on side 2                  =    0.00E+00

The mesh quality thresholds that define the OK (good), ok (acceptable), and ! (poor) status in the mesh statistics section of the OUT file are as follows:

Maximum aspect ratio (double precision) | OK | <10000.0
ok | 10000.0 < 100000.0
! | > 100000.0
Maximum aspect ratio (single precision) | OK | < 100.0
ok | 100.0 < 1000.0
! | > 1000.0
Maximum mesh expansion factor | OK | < 5.0
ok | 5.0 < 20.0
! | > 20.0
Minimum orthogonal angle | OK | > 50°
ok | 50° > 20°
! | < 20°

Note: Negative orthogonality angles are possible and indicate the presence of very poor mesh elements that can adversely affect solution quality. It is recommended that meshes not contain any negative orthogonality angles.

#### 3.2.1.6. Initial Average Scales

These are average scales based on the initial flow field. If the initial velocity field is zero, then the initial average velocity scale will also be zero.

The section for initial average scales looks similar to the following:

    +--------------------------------------------------------------------+
    |                      Average Scale Information                     |
    +--------------------------------------------------------------------+
    Domain Name : StaticMixer
         Global Length                                       =  3.2113E+00
         Density                                             =  9.9800E+02
         Dynamic Viscosity                                   =  1.0000E-03
         Velocity                                            =  0.0000E+00
         Thermal Conductivity                                =  5.9100E-01
         Specific Heat Capacity at Constant Pressure         =  4.1900E+03
         Prandtl Number                                      =  7.0897E+00

#### 3.2.1.7. Checking for Isolated Fluid Regions

For serial runs, the solver checks to see if any fluid domain contains volumetric regions that are isolated pockets. This check cannot be performed for parallel solver runs.

#### 3.2.1.8. Solved Equations

This section lists the dependent variables solved and the equations to which they relate as well as the estimated physical timestep if calculated automatically.

Equations are given two labels: the individual name and a combined name used for combining residuals together. Residuals for multi-domain problems are combined provided the domains are connected together and have the same domain type (solid or fluid/porous). If there are multiple groups of the same domain type, then the group residual is identified by the name of the first domain in the connected group.

The section for solved equations looks similar to the following:

     +--------------------------------------------------------------------+
     |              The Equations Solved in This Calculation              |
     +--------------------------------------------------------------------+
     Subsystem : Momentum and Mass
       U-Mom
       V-Mom
       W-Mom
       P-Mass
     Subsystem : Thermal Radiation
       I-Radiation
     Subsystem : Heat Transfer
       H-Energy
     Subsystem : Temperature Variance
       T-Variance
     Subsystem : TurbKE and Diss.K
       K-TurbKE
       E-Diss.K
     Subsystem : Mixture Fraction
       Z-Mean
       Z-Variance
     Subsystem : Mass Fractions
       NO-Mass Fraction

#### 3.2.1.9. Convergence History

The convergence history section details the state of the solution as it progresses. Equation residual information at specified locations enables you to monitor the convergence. Convergence difficulties can often be pinpointed to a particular part of the solution (for example, the momentum equation), and/or a particular location.

The tables shown in the convergence history have the following columns:

- Rate

  The rate is defined as seen in Equation 3–1 where is the residual at iteration , and is the residual at an earlier iteration. Rates less than 1.0 indicate convergence.

  | (3–1)

- RMS Res

  The value of the root mean square normalized residual taken over the whole domain.

- Max Res

  The value of the maximum normalized residual in the domain.

- Linear Solution

  The three columns in this section refer to the performance of the linear (inner) solvers. The first column is the average number of iterations the linear solvers attempted to obtain the specified linear equation convergence criteria (within a specified number of iterations). The second column gives the normalized residuals for the solutions to the linear equation. The last column can have one of four entries:

  - `*` indicates that there was a numerical floating point exception and this resulted in the failure of the linear solvers.

  - `F` indicates that the linear solvers did not reduce the residuals (that is, the solution was diverging), but the linear solvers may carry on if the divergence is not catastrophic.

  - `ok` indicates that the residuals were reduced, but that the degree of reduction did not meet the specified criteria.

  - `OK` indicates that the specified convergence criteria for the reduction of residuals was achieved.

After the convergence criteria has been achieved, or the specified number of timesteps has been reached, CFX-Solver appends additional information, calculated from the solution, to the CFX-Solver Output file.

The convergence history for a steady state analysis looks similar to the following:

    +--------------------------------------------------------------------+
    |                       Convergence History                          |
    +--------------------------------------------------------------------+
    ======================================================================
    OUTER LOOP ITERATION =    1                     CPU SECONDS = 2.68E+00
    ----------------------------------------------------------------------
    |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |
    +----------------------+------+---------+---------+------------------+
    | U - Mom              | 0.00 | 1.5E-10 | 5.4E-09 |       1.5E+10  ok|
    | V - Mom              | 0.00 | 1.6E-04 | 3.2E-03 |       6.4E+01  ok|
    | W - Mom              | 0.00 | 2.5E-10 | 6.4E-09 |       1.1E+10  ok|
    | P - Mass             | 0.00 | 2.2E-03 | 3.0E-02 | 12.0  9.5E-02  OK|
    +----------------------+------+---------+---------+------------------+
    | H-Energy             | 0.00 | 3.6E-03 | 3.6E-02 |  5.4  8.0E-03  OK|
    +----------------------+------+---------+---------+------------------+
    ======================================================================
    OUTER LOOP ITERATION =    2                     CPU SECONDS = 1.24E+01
    ----------------------------------------------------------------------
    |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |
    +----------------------+------+---------+---------+------------------+
    | U - Mom              |99.99 | 5.2E-03 | 7.5E-02 |       4.8E-02  OK|
    | V - Mom              |99.76 | 1.6E-02 | 1.6E-01 |       1.4E-02  OK|
    | W - Mom              |99.99 | 8.4E-03 | 1.2E-01 |       7.9E-02  OK|
    | P - Mass             | 4.26 | 9.3E-03 | 1.3E-01 |  8.3  8.4E-02  OK|
    +----------------------+------+---------+---------+------------------+
    | H-Energy             | 0.35 | 1.3E-03 | 8.8E-03 |  9.4  2.9E-03  OK|
    +----------------------+------+---------+---------+------------------+
    ................
    ................
    ======================================================================
    OUTER LOOP ITERATION =   29                     CPU SECONDS = 2.44E+02
    ----------------------------------------------------------------------
    |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |
    +----------------------+------+---------+---------+------------------+
    | U - Mom              | 0.86 | 7.7E-05 | 3.1E-04 |       5.1E-02  OK|
    | V - Mom              | 0.86 | 9.1E-05 | 3.7E-04 |       4.8E-02  OK|
    | W - Mom              | 0.86 | 1.9E-05 | 1.6E-04 |       5.0E-02  OK|
    | P - Mass             | 0.87 | 3.7E-05 | 1.7E-04 |  8.3  3.0E-02  OK|
    +----------------------+------+---------+---------+------------------+
    | H-Energy             | 0.86 | 5.7E-06 | 5.5E-05 |  9.5  9.8E-03  OK|
    +----------------------+------+---------+---------+------------------+
    CFD Solver finished: Wed Oct 25 16:01:48 2000
    CFD Solver wall clock seconds: 1.0000E+00

If a steady state analysis is continued, then the outer loop iterations and CPU seconds for the current run are enclosed in parenthesis, as shown below. Values not enclosed in parenthesis are the totals for the overall analysis.

    ======================================================================
    OUTER LOOP ITERATION =   30 (    1) CPU SECONDS = 2.48E+02 ( 3.38E+00)
    ----------------------------------------------------------------------
    |       Equation       | Rate | RMS Res | Max Res |  Linear Solution |
    +----------------------+------+---------+---------+------------------+
    | U - Mom              | 0.00 | 1.5E-04 | 1.2E-03 |       4.6E-02  OK|
    | V - Mom              | 0.00 | 2.1E-04 | 1.2E-03 |       3.8E-02  OK|
    | W - Mom              | 0.00 | 1.5E-04 | 2.1E-03 |       1.3E-02  OK|
    | P - Mass             | 0.00 | 3.2E-05 | 1.5E-04 |  8.3  3.4E-02  OK|
    +----------------------+------+---------+---------+------------------+
    | H-Energy             | 0.00 | 7.7E-06 | 8.5E-05 |  9.5  9.1E-03  OK|
    +----------------------+------+---------+---------+------------------+

#### 3.2.1.10. Computed Model Constants

If the Zero Equation model is used to model turbulence, the overall turbulence viscosity is provided.

The section for computed model constants looks similar to the following:

    +--------------------------------------------------------------------+
    |                      Computed Model Constants                      |
    +--------------------------------------------------------------------+
    Turbulence viscosity for Turbulence Model 1   = 3.3667E+00

#### 3.2.1.11. Termination and Interrupt Condition Summary

After executing each coefficient iteration and time step (or outer iteration), the solver evaluates all internal termination conditions and user-defined interrupt control conditions. After a termination or interrupt, any of these conditions that are true are reported in the CFX-Solver Output file as outlined below.

     ======================================================================
                   Termination and Interrupt Condition Summary
     ======================================================================
    CFD Solver: <internal termination condition description>
    User: <interrupt condition object name>

#### 3.2.1.12. Global Conservation Statistics

Global conservation statistics are generated for all transport equations with the exception of turbulence equations, which have special wall treatment. These are good checks for the convergence of a solution. Small values of global imbalance indicate that conservation has essentially been achieved.

The percentage imbalance of a quantity is calculated as:

where “” is taken to be the largest contribution in all connected domains for the specific group of equations. The grouping of equations for the purpose of normalization can be different depending on the case.

For single-phase calculations, each equation imbalance is normalized using the largest contribution for that equation subsystem. The exception is the hydrodynamic subsystem, where each momentum equation imbalance is normalized using the largest contribution from all momentum equations, and the continuity equation imbalance is normalized using the largest contribution in all continuity equations.

For Eulerian multiphase cases, the imbalance normalization can be across all phases or within a single phase for any equation, depending on the physics and whether coupled volume fractions are employed. A summary table of how each equation normalization is performed is given below:

Equation | Normalization
--- | ---
| Segregated VFs | Coupled VFs
Momentum | All Phases | All Phases
Energy | All Phases | All Phases
Mass | Each Phase | All Phases
Mass [a] | Each Phase | All Phases
Components | Each Phase | Each Phase
Components [b] | All Phases | All Phases
Additional Variables | Each Phase | Each Phase
Additional Variables [c] | All Phases | All Phases
[a] Physics includes interphase mass transfer. [b] Physics includes interphase component transfer. [c] Physics includes interphase Additional Variable transfer.

The section for global conservation statistics looks similar to the following:

     ======================================================================
                  Boundary Flow and Total Source Term Summary
     ======================================================================

     +--------------------------------------------------------------------+
     |                               U-Mom                                |
     +--------------------------------------------------------------------+
     Boundary         : CatConv Default                        -9.4754E-01
     Boundary         : Inlet                                   1.6971E+00
     Boundary         : InletSide Side 1                        1.3262E-05
     Boundary         : Outlet                                 -1.0523E+00
     Boundary         : OutletSide Side 1                      -1.7085E-07
     Sub-Domain       : catalyst                                2.6129E-01
     Neg Accumulation : CatConv                                 4.1436E-02
     Domain Interface : InletSide (Side 1)                     -1.1166E-02
     Domain Interface : InletSide (Side 2)                      1.1166E-02
     Domain Interface : OutletSide (Side 1)                    -1.4308E-05
     Domain Interface : OutletSide (Side 2)                     1.4308E-05
                                                               -----------
     Domain Imbalance :                                        -3.6059E-05

     Domain Imbalance, in %:                                     -0.0002 %

     +--------------------------------------------------------------------+
     |                               V-Mom                                |
     +--------------------------------------------------------------------+
     Boundary         : CatConv Default                        -3.3355E-02
     Boundary         : Inlet                                   1.1009E-07
     Boundary         : InletSide Side 1                        7.2564E-06
     Boundary         : Outlet                                 -4.7561E-04
     Boundary         : OutletSide Side 1                       1.9734E-08
     Sub-Domain       : catalyst                                3.4056E-02
     Neg Accumulation : CatConv                                -2.4319E-04
     Domain Interface : InletSide (Side 1)                     -4.7260E-04
     Domain Interface : InletSide (Side 2)                      4.7262E-04
     Domain Interface : OutletSide (Side 1)                     7.5672E-06
     Domain Interface : OutletSide (Side 2)                    -7.5672E-06
                                                               -----------
     Domain Imbalance :                                        -1.0275E-05

     Domain Imbalance, in %:                                      0.0000 %

     +--------------------------------------------------------------------+
     |                               W-Mom                                |
     +--------------------------------------------------------------------+
     Boundary         : CatConv Default                        -1.1450E+01
     Boundary         : Inlet                                  -1.6971E+00
     Boundary         : InletSide Side 1                        1.3180E-01
     Boundary         : Outlet                                  1.0628E+00
     Boundary         : OutletSide Side 1                      -6.8369E-02
     Sub-Domain       : catalyst                                1.2137E+01
     Neg Accumulation : CatConv                                -1.8195E-01
     Domain Interface : InletSide (Side 1)                      2.2715E+01
     Domain Interface : InletSide (Side 2)                     -2.2592E+01
     Domain Interface : OutletSide (Side 1)                    -1.0548E+01
     Domain Interface : OutletSide (Side 2)                     1.0493E+01
                                                               -----------
     Domain Imbalance :                                         1.4353E-03

     Domain Imbalance, in %:                                      0.0063 %

     +--------------------------------------------------------------------+
     |                               P-Mass                               |
     +--------------------------------------------------------------------+
     Boundary         : Inlet                                   2.8382E-02
     Boundary         : Outlet                                 -5.6938E-02
     Neg Accumulation : CatConv                                 2.8576E-02
     Domain Interface : InletSide (Side 1)                     -3.0665E-02
     Domain Interface : InletSide (Side 2)                      3.0665E-02
     Domain Interface : OutletSide (Side 1)                     5.6543E-02
     Domain Interface : OutletSide (Side 2)                    -5.6543E-02
                                                               -----------
     Domain Imbalance :                                         2.0828E-05

     Domain Imbalance, in %:                                      0.0366 %

     +--------------------------------------------------------------------+
     |                            I-Radiation                             |
     +--------------------------------------------------------------------+
     Boundary         : CatConv Default                        -1.4392E+01
     Boundary         : Inlet                                   1.9442E+01
     Boundary         : InletSide Side 1                        3.8307E-01
     Boundary         : Outlet                                 -6.1793E+00
     Boundary         : OutletSide Side 1                      -1.7803E-01
     Domain Src (Neg) : CatConv                                -2.9646E-01
     Domain Src (Pos) : CatConv                                 3.0447E-01
     Domain Interface : InletSide (Side 1)                     -4.6702E+02
     Domain Interface : InletSide (Side 2)                      4.6702E+02
     Domain Interface : OutletSide (Side 1)                    -7.4487E+01
     Domain Interface : OutletSide (Side 2)                     7.4490E+01
                                                               -----------
     Domain Imbalance :                                        -9.0640E-01

     Domain Imbalance, in %:                                     -0.1941 %

     +--------------------------------------------------------------------+
     |                              H-Energy                              |
     +--------------------------------------------------------------------+
     Boundary         : CatConv Default                         1.4284E+01
     Boundary         : Inlet                                   8.6049E+03
     Boundary         : InletSide Side 1                       -3.8344E-01
     Boundary         : Outlet                                 -2.3960E+02
     Boundary         : OutletSide Side 1                       1.7809E-01
     Domain Src (Neg) : CatConv                                -3.0461E-01
     Domain Src (Pos) : CatConv                                 2.9616E-01
     Neg Accumulation : CatConv                                -8.3717E+03
     Domain Interface : InletSide (Side 1)                     -7.6620E+03
     Domain Interface : InletSide (Side 2)                      7.6620E+03
     Domain Interface : OutletSide (Side 1)                     1.3624E+02
     Domain Interface : OutletSide (Side 2)                    -1.3624E+02
                                                               -----------
     Domain Imbalance :                                         7.6699E+00

     Domain Imbalance, in %:                                      0.0891 %

An example section that shows how the imbalance for each transport equation is normalized:

    +--------------------------------------------------------------------+
    |                     Normalised Imbalance Summary                   |
    +--------------------------------------------------------------------+
    |       Equation       |      Maximum Flow     |     Imbalance (%)   |
    +--------------------------------------------------------------------+
    | U-Mom-Fluid 2        |       6.0270E+02      |       15.9327       |
    | V-Mom-Fluid 2        |       6.0270E+02      |        0.0000       |
    | W-Mom-Fluid 2        |       6.0270E+02      |        0.0004       |
    | U-Mom-Fluid 1        |       6.0270E+02      |      -16.6732       |
    | V-Mom-Fluid 1        |       6.0270E+02      |        0.0001       |
    | W-Mom-Fluid 1        |       6.0270E+02      |        0.0004       |
    | Mass-Fluid 2         |       5.9820E+02      |       16.2942       |
    | Mass-Fluid 1         |       5.9820E+02      |      -16.2929       |
    +----------------------+-----------------------+---------------------+
    +----------------------+-----------------------+---------------------+
    | H-Energy-Fluid 2     |       3.7642E+07      |     -136.9703       |
    | H-Energy-Fluid 1     |       3.7642E+07      |      -76.2664       |
    +----------------------+-----------------------+---------------------+

For more details, see Monitoring and Obtaining Convergence in the CFX-Solver Modeling Guide.

#### 3.2.1.13. Calculated Wall Forces and Moments

The CFX-Solver calculates the pressure and viscous components of forces on all boundaries specified as walls. The drag force on any wall can be calculated from these values as follows:

Lift is the net force on the body in the direction perpendicular to the direction of flow. In the above diagram, the lift is the sum of the forces on the wall in the vertical direction, that is, the sum of the pressure force and the viscous force components in the y direction.

Drag is the net force on the body in the direction of the flow. In the above diagram, the drag is the sum of the forces on the wall in the horizontal direction, that is, the sum of the pressure force and the viscous force components in the x direction.

It is apparent from this that viscous force is not a pure shear force because it also has a small component in the normal direction, arising in part from a normal component in the laminar flow shear stress.

The pressure and viscous moments are related to the pressure and viscous forces calculated at the wall. The pressure moment is the vector product of the pressure force vector and the position vector . The viscous moment is the vector product of the viscous force vector and the position vector . As an example, review Equation 3–2 where and are the pressure and viscous moments respectively.

| (3–2)

These are summed over all the surface elements in the wall.

It is important to note that forces are evaluated in the local reference frame and that they do not include reference pressure effects. The pressure force is calculated as the integral of the relative pressure over the wall area and not as the integral of the sum of the reference and relative pressures. You can include reference pressure effects in the force calculation by setting the expert parameter `include pref in forces = t`.

It is also important to note that for rotating domains in a transient run, forces are evaluated in the reference frame fixed to the initial domain orientation. These quantities are not influenced by any rotation that might occur during a transient run or when a rotational offset is specified. However, results for rotating domains in a transient run may be in the rotated position (depending on the setting of Options in CFD-Post) when they are subsequently loaded into CFD-Post for post-processing.

The sections for calculated wall forces and moments look similar to the following:

     ======================================================================
                         Wall Force and Moment Summary
     ======================================================================

     Notes:
     1. Pressure integrals exclude the reference pressure.  To include
        it, set the expert parameter 'include pref in forces = t'.

     +--------------------------------------------------------------------+
     |                      Pressure Force On Walls                       |
     +--------------------------------------------------------------------+
                                        X-Comp.      Y-Comp.      Z-Comp.

     Domain Group: Bottom Box

     Copy of Walls                    7.5841E+01   8.4350E+01  -5.2096E+02
     Top Box Default                 -5.4841E+01   0.0000E+00   0.0000E+00
     Walls                            4.8468E+01   1.2755E+02   5.0230E+02
                                      -----------  -----------  -----------
     Domain Group Totals :            6.9468E+01   2.1190E+02  -1.8659E+01

     +--------------------------------------------------------------------+
     |                       Viscous Force On Walls                       |
     +--------------------------------------------------------------------+
                                        X-Comp.      Y-Comp.      Z-Comp.

     Domain Group: Bottom Box

     Copy of Walls                   -3.4280E-04  -1.8638E-03  -5.7310E-04
     Top Box Default                 -4.7982E-05   5.5391E-06  -2.2129E-05
     Walls                            2.9180E-04  -4.3111E-05  -6.2137E-04
                                      -----------  -----------  -----------
     Domain Group Totals :           -9.8980E-05  -1.9014E-03  -1.2166E-03

#### 3.2.1.14. Maximum Residual Statistics

The locations of the maximum residuals are very important when identifying and/or quantifying the root cause of solution convergence difficulties. If there is trouble converging to a steady-state solution and the maximum residuals are large, take the following steps:

1. In the .out file, identify the equation that has the largest maximum (not RMS) residuals in the diagnostics section for the final iteration (see Convergence History). Specifically, look at the momentum, mass, and energy equations’ maximum residuals.

2. Find the `Locations of Maximum Residuals` table near the bottom of the .out file, and identify the domain and node number for the equation with the largest maximum residual.

3. Create a point locator in CFD-Post using the domain and node number identified above by setting Geometry > Method to `Node Number`. For details, see Point: Geometry in the CFD-Post User's Guide.

The sections for maximum residual statistics look similar to the following:

     +--------------------------------------------------------------------+
     |               Locations of Maximum Residuals                       |
     +--------------------------------------------------------------------+
     |       Equation       |      Domain Name      |     Node Number     |
     +--------------------------------------------------------------------+
     | U-Mom                | Domain 1              |              34     |
     | V-Mom                | Domain 1              |               4     |
     | W-Mom                | Domain 2              |              61     |
     | P-Mass               | Domain 1              |              61     |
     +----------------------+-----------------------+---------------------+
     | H-Energy             | Domain 2              |              61     |
     +----------------------+-----------------------+---------------------+
     | H2O-Mass Fraction    | Domain 1              |              57     |
     | C2H6O-Mass Fraction  | Domain 1              |               1     |
     | C10H22-Mass Fraction | Domain 2              |              61     |
     +----------------------+-----------------------+---------------------+

The presence of regions of low mesh quality is the most common cause of stalled convergence. A common cause of stalled convergence within steady-state simulations is the presence of recirculating flow or local flow separation. Try to correlate the cause of stalled convergence to the location of the maximum residual in CFD-Post. Check for poor mesh quality, separating flow, reattaching flow, etc. in this location to determine whether the lack of tight convergence is caused by a problem that can be solved (for example, by improving the mesh in this region), or caused by a tolerable oscillation (for example, if some transient flow phenomena is being resolved in an otherwise steady-state flow simulation).

#### 3.2.1.15. False Transient Information

This is only applicable to steady-state simulations (serial and parallel). The information is equation based, that is there is one line per equation solved. For each equation, the type of timestepping used is displayed as `Auto`, `Physical` or `Local`.

Both `Auto` and `Physical` run as false transients. This means that although the simulation is steady state, a transient term with an associated timestep is used to relax the equations during convergence. In this case, the total elapsed pseudo-time is also printed.

The section for false transient information looks similar to the following:

    +--------------------------------------------------------------------+
    |                   False Transient Information                      |
    +--------------------------------------------------------------------+
    |       Equation       |       Type        |   Elapsed Pseudo-Time   |
    +--------------------------------------------------------------------+
    | U - Mom              | Physical          |      5.80000E+01        |
    | V - Mom              | Physical          |      5.80000E+01        |
    | W - Mom              | Physical          |      5.80000E+01        |
    | P - Mass             | Physical          |      5.80000E+01        |
    | H-Energy             | Physical          |      5.80000E+01        |
    +--------------------------------------------------------------------+

#### 3.2.1.16. Final Average Scales

These are average scales for the final flow field.

The section for final average scales looks similar to the following:

    +--------------------------------------------------------------------+
    |                     Average Scale Information                      |
    +--------------------------------------------------------------------+
    Domain Name : StaticMixer
    	Global Length                                       =  3.2113E+00
    	Density                                             =  9.9800E+02
    	Dynamic Viscosity                                   =  1.0000E-03
    	Velocity                                            =  1.4534E+00
    	Advection Time                                      =  2.2095E+00
    	Reynolds Number                                     =  4.6581E+06
    	Thermal Conductivity                                =  5.9100E-01
    	Specific Heat Capacity at Constant Pressure         =  4.1900E+03
    	Prandtl Number                                      =  7.0897E+00
    	Temperature Range                                   =  3.0008E+01

#### 3.2.1.17. Variable Range Information

These are the maximum and minimum values for each variable in the flow field.

The section for variable range information looks similar to the following:

    +--------------------------------------------------------------------+
    |                     Variable Range Information                     |
    +--------------------------------------------------------------------+
    Domain Name : StaticMixer
    +--------------------------------------------------------------------+
    |      Variable Name                         |    min    |    max    |
    +--------------------------------------------------------------------+
    | Velocity u                                 | -1.65E+00 |  1.61E+00 |
    | Velocity v                                 | -2.26E+00 |  2.25E+00 |
    | Velocity w                                 | -4.13E+00 |  2.58E-01 |
    | Pressure                                   | -6.71E+02 |  1.38E+04 |
    | Density                                    |  9.98E+02 |  9.98E+02 |
    | Dynamic Viscosity                          |  1.00E-03 |  1.00E-03 |
    | Specific Heat Capacity at Constant Pressure|  4.19E+03 |  4.19E+03 |
    | Thermal Conductivity                       |  5.91E-01 |  5.91E-01 |
    | Thermal Expansivity                        |  2.10E-04 |  2.10E-04 |
    | Eddy Viscosity                             |  1.89E+01 |  1.89E+01 |
    | Temperature                                |  2.85E+02 |  3.15E+02 |
    | Static Enthalpy                            |  1.19E+06 |  1.32E+06 |
    +--------------------------------------------------------------------+

#### 3.2.1.18. CPU Requirements

The section for CPU requirements looks similar to the following:

     +--------------------------------------------------------------------+
     |           CPU Requirements of Numerical Solution - Total           |
     +--------------------------------------------------------------------+

     Subsystem Name                  Discretization       Linear Solution
                                    (secs.   %total)     (secs.   %total)
     ----------------------------------------------------------------------
     Momentum and Mass              2.50E-01  10.5 %     7.81E-02   3.3 %
                                    -------- -------     --------  ------
     Subsystem Summary              2.50E-01  10.5 %     7.81E-02   3.3 %

     Variable Updates               1.25E-01   5.3 %
     File Reading                   1.41E-01   5.9 %
     File Writing                   6.25E-02   2.6 %
     Miscellaneous                  1.72E+00  72.4 %
                                    --------
     Total                          2.38E+00

#### 3.2.1.19. Job Information at End of Run

The section for job information looks similar to the following:

     +--------------------------------------------------------------------+
     |                   Job Information at End of Run                    |
     +--------------------------------------------------------------------+

     +---------------------------+------+----------+----------+-----------+
     | Host                      | Mesh |     Job Finished    |    CPU    |
     |                           | Part | DD/MM/YY | hh:mm:ss |  seconds  |
     +---------------------------+------+----------+----------+-----------+
     | Host1                     |    1 | 25/10/12 | 11:39:49 | 7.912E+00 |
     +---------------------------+------+----------+----------+-----------+

     Total wall clock time: 8.405E+00 seconds
                 or: (          0:         0:         0:     8.405 )
                     (       Days:     Hours:   Minutes:   Seconds )

Release 18.2 - © ANSYS, Inc. All rights reserved.