### 21.1.5. Monitor Tab

The Monitor tab for the `Output Control` object contains settings that specify monitor output. The following types of information can be monitored as a solution proceeds:

- Primitive or derived solution variables

- Fluid Properties

- Expressions.

When monitoring expressions, the expression must evaluate to a single number; for details, see Working with Monitors.

#### 21.1.5.1. Monitor Objects Check Box

This check box determines whether or not monitor data is generated as a solution proceeds. If it is selected, the following settings are available:

##### 21.1.5.1.1. Monitor Coeff. Loop Convergence

(applies only for transient cases)

This check box determines whether or not monitor data is output within coefficient (inner) loops. Regardless of the setting, data will be output for each timestep.

##### 21.1.5.1.2. Monitor Balances: Option

- `Full`

  Mass, Momentum, and other balances are written to the solver monitor file.

- `None`

##### 21.1.5.1.3. Monitor Forces: Option

- `Full`

  Forces and moments on wall boundaries are written to the solver monitor file.

  It is important to note that these forces and moments do not include reference pressure effects. 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 and moments on wall boundaries 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 postprocessing.

- `None`

##### 21.1.5.1.4. Monitor Residuals: Option

- `Full`

  RMS/max residuals are written to the solver monitor file.

- `None`

##### 21.1.5.1.5. Monitor Totals: Option

- `Full`

  Flow and source totals (integrals over boundaries) are written to the solver monitor file.

- `None`

##### 21.1.5.1.6. Monitor Particles: Option

- `Full`

  If Lagrangian Particle Tracking information is included in the simulation, force, momentum, energy, mass flow rates, and source data for particles are written to the solver monitor file.

- `None`

##### 21.1.5.1.7. Efficiency Output Check Box

This check box determines whether or not the device efficiency can be monitored in CFX-Solver Manager. When selected it also activates field efficiency output to CFD-Post. If activated, the following information must be specified:

###### 21.1.5.1.7.1. Inflow Boundary

A single boundary condition region of type INLET.

###### 21.1.5.1.7.2. Outflow Boundary

A single boundary condition region of type OUTLET.

###### 21.1.5.1.7.3. Efficiency Type

Choose between Compression, Expansion, and Both Compression and Expansion.

For more information, see Activating Efficiency Output

###### 21.1.5.1.7.4. Efficiency Calculation Method

For each of the efficiency types, two efficiency calculation options are possible: Total to Total and Total to Static.

For more information, see Isentropic Efficiency and Total Enthalpy

##### 21.1.5.1.8. Monitor Points And Expressions List Box

This list box is used to select monitor point and expression objects for editing or deletion. These objects can be created or deleted with the icons that appear beside the list box.

###### 21.1.5.1.8.1. [Monitor Name]: Option

- `Cartesian Coordinates`

  Monitor point data includes variable values at the node closest to the specified point. A crosshair will be displayed in the viewer to indicate the monitored node.

- `Cylindrical Coordinates`

  Specify the monitor point location in terms of Position Axial Comp., Position Radial Comp., and Position Theta Comp. values.

  Monitor point data includes variable values at the node closest to the specified point. A crosshair will be displayed in the viewer to indicate the monitored node.

  Note: This option disables the ability to specify the points by picking in the Viewer.

- `Expression`

  An expression is monitored.

###### 21.1.5.1.8.2. [Monitor Name]: Output Variables List

(applies only when Option is set to `Cartesian Coordinates` or `Cylindrical Coordinates`)

Select the variables to monitor.

Tip: Hold the Ctrl key when clicking to select multiple variables.

###### 21.1.5.1.8.3. [Monitor Name]: Cartesian Coordinates

(applies only when Option is set to `Cartesian Coordinates`)

Enter coordinates for the point location to monitor.

Tip: After you click a coordinate entry area, all of the coordinate entry areas turn yellow to show that you are in Picking mode. You can then select locations from the viewer using the mouse. To manipulate the object in the viewer while in Picking mode, use the viewer icons (rotate, pan, zoom) in the toolbar. You can end Picking mode by changing the keyboard focus (by clicking in another field, for example).

###### 21.1.5.1.8.4. [Monitor Name]: Cylindrical Coordinates

(applies only when Option is set to `Cylindrical Coordinates`)

Enter coordinates for the point location to monitor in terms of Position Axial Comp., Position Radial Comp., and Position Theta Comp. values.

Note: This option disables the ability to specify the points by picking in the Viewer.

Cylindrical coordinates are defined with respect to the global coordinate frame, unless a local coordinate frame is selected.

###### 21.1.5.1.8.5. [Monitor Name]: Expression Value

(applies only when Option is set to `Expression`)

Enter a CEL expression that evaluates to a single number that is to be monitored.

###### 21.1.5.1.8.6. [Monitor Name]: Coordinate Frame

Set the coordinate frame used for the monitor point or expression; for details, see Coordinate Frames in the CFX-Solver Modeling Guide.

For a monitor point that uses Cartesian or cylindrical coordinates, the coordinate frame is used to interpret the specified coordinates. For a monitor point that uses an expression, the coordinate frame affects all CEL functions that are used in the expression and that return the component of a vector (for example, `force_x()`).

###### 21.1.5.1.8.7. [Monitor Name]: Monitor Location Control

(applies only when Option is set to `Cartesian Coordinates` or `Cylindrical Coordinates`)

Monitor Location Control settings determine where the monitor is placed with respect to the mesh, and how often the monitor position is updated. The following Monitor Location Control options are available:

Interpolation Type

  - `Nearest Vertex`

    This option causes monitor point data to be taken from the mesh vertex nearest to the specified coordinates. The nearest mesh vertex is determined initially and again every time the monitor position is updated (based on the Position Update Frequency setting).

  - `Trilinear`

    This option causes monitor point data to be interpolated to the specified coordinates using a weighted average of the data from the vertices of the containing mesh element. The containing mesh element, and the values of the weighting factors, are determined initially and again every time the position is updated (based on the Position Update Frequency setting).

  Note: If Interpolation Type is set to `Trilinear` and the specified coordinates are not contained by the current mesh, CFX-Solver reverts to `Nearest Vertex` behavior. As a result, you may receive unexpected monitor output. However, if the monitor position updates, normal `Trilinear` behavior resumes whenever the coordinates are contained by the mesh. This might occur if the simulation includes a moving mesh or a stationary monitor point in a rotating domain.

Domain Name

  - If the check box is selected, you must set the domain name to which the specified coordinates will be restricted.

  - If the check box is cleared, CFX-Solver searches over all domains for a location match. In this case, the matching domain for a stationary monitor point can potentially change each time the monitor point is updated. This might occur if, for example, the simulation includes a moving mesh or has multiple frames of reference.

Frame Type

  - If the check box is selected, choose whether the specified coordinates are relative to the `Local` frame (which could be rotating) or the `Stationary` frame. If the simulation involves transient rotating domains, and the frame type is set to `Stationary`, then the monitor location will acknowledge any rotational periodic interfaces that you have set up, and periodic expansion will be assumed.

  - If the check box is cleared, the specified coordinates are, by default, relative to the local frame.

  Note: If you position a stationary monitor point too close to a frame-change interface, such as a Transient Rotor-Stator or sliding mesh interface, then the monitor point may not consistently find the nearest vertices in the same domain as the mesh moves. This can lead to unpredictable output values from the monitor. You should restrict such monitors to one of the domains on either side of the interface using Domain Name.

Position Update Frequency

  Determine how frequently the monitor position is updated, if at all. This option is relevant only in simulations that include a moving mesh or transient rotating domains (steady-state rotating domains are frozen and, therefore, do not actually rotate). Otherwise, the monitor point interpolation does not change and the position remains constant.

  - `Initial Mesh Only`

    The monitor point interpolation is based on the initial mesh.

  - `Every Timestep` or `Every Iteration`

    The monitor point interpolation is updated as the simulation proceeds.

###### 21.1.5.1.8.8. [Monitor Name]: Monitor Statistics

(applies only when Option is set to `Expression`)

You can select one or more statistical quantities (for example, `Arithmetic Average` and `Standard Deviation`) to be evaluated for the expression value over a moving interval. This interval represents the recent history of the solution. When you run the simulation, CFX-Solver computes the statistical quantities in addition to the expression value.

Note:

- Monitor statistics are not supported for cases that use variable time steps.

- You can refer to monitor statistics in CEL expressions. For details, see Using Monitors in CEL.

The following Monitor Statistics options are available:

Interval Option

  Control how frequently the values of the selected statistics are updated. Each update, the values are calculated using the most recent iterations that fit into the interval.

  - `Moving Interval`

    Updates statistical values every iteration.

  - `Previous Complete Interval`

    Updates statistical values at the completion of the previous interval. The values remain fixed until each subsequent interval is complete.

  Note: Statistical quantities are only plotted for complete intervals, and will not be displayed before the first interval is complete.

Statistics List

  Select statistics for CFX-Solver to evaluate. You can select multiple statistics using the Ctrl key.

  - `Arithmetic Sum`

    Sums all values of the monitor within the current interval.

  - `Arithmetic Average`

    Calculates the arithmetic mean of the current interval.

  - `Difference from the Mean`

    Subtracts the arithmetic average of the current interval from the monitor value at the end of the interval.

  - `Maximum`

    Displays the maximum monitor value that occurs within the current interval.

  - `Minimum`

    Displays the minimum monitor value that occurs within the current interval.

  - `Root Mean Square`

    Calculates the square root of the arithmetic mean of the squares of the monitor values within the current interval.

  - `Standard Deviation`

    Calculates the sample standard deviation of the current interval.

  - `Time Integral`

    Approximates the time integral of the monitor over the interval, where time is in solution units. This option is available only for transient simulations.

Interval Definition

  Control the size of the evaluation interval. You can select different options for steady-state and transient cases.

  The following options are available for steady-state cases:

  - `Iteration`

    Specifies the interval as a number of solver iterations.

  The following settings are available for transient cases:

  - `Time Period`

    Specifies the interval as a number of operational periods. This setting is only available to transient blade row cases. The period length is the value set in the `Transient Blade Row Models` object, under Transient Method > Time Period.

  - `Time`

    Specifies the interval as an amount of simulation time.

  - `Timestep`

    Specifies the interval as a number of time steps.

  Note: When a case with a monitor statistic is restarted with a different Interval Definition setting, the statistic may be discontinuous at the start of the simulation.

##### 21.1.5.1.9. Aerodynamic Damping: Frame Overview

Aerodynamic damping monitors are available for transient blade row cases that involve wall boundaries that have the `Periodic Displacement` mesh motion boundary condition.

Aerodynamic damping per vibration cycle is a measure of the net energy transferred mechanically from the blade to the fluid over one vibration cycle of the blade. The damping value is evaluated by computing the total work that the blade surface imparts on the fluid over the time period corresponding to a given mode of vibration. For details on the calculation, see Equation 6–2 in the CFX-Solver Modeling Guide.

A positive value of aerodynamic damping indicates that the vibration is damped (for the frequency being studied). Conversely, a negative value of aerodynamic damping indicates that the vibration is undamped.

##### 21.1.5.1.10. Aerodynamic Damping List Box

This list box is used to select aerodynamic damping monitor objects for editing or deletion. These objects can be created or deleted with the icons that appear beside the list box.

##### 21.1.5.1.11. Aerodynamic Damping: [Aerodynamic Damping Name]: Option

- `Full Period Integration`

  With this option set, the damping value calculation involves an integration over the last complete integration interval. In this context, the first integration interval starts at the beginning of the run (or, in the case of restarts, the initial run). The size of an integration interval is displayed as a read-only value, as described below. The damping value is calculated only upon the completion of each integration interval.

- `Moving Integration Interval`

  With this option set, the damping value calculation involves an integration over a time interval that has a duration of one integration interval and that ends at the current time step. The damping value is calculated for each time step.

##### 21.1.5.1.12. Aerodynamic Damping: [Aerodynamic Damping Name]: Normalization

Enter a value and units for normalization of the aerodynamic damping value. The aerodynamic damping value, which has units of energy and represents the work done per period, is normalized by the specified normalization value, which also has units of energy, resulting in a dimensionless normalized value of aerodynamic damping.

##### 21.1.5.1.13. Aerodynamic Damping: [Aerodynamic Damping Name]: Location Type

Specify a mesh region or a boundary that represents the surface over which integration is carried out as part of the aerodynamic damping calculation. Only boundaries that have a `Periodic Displacement` mesh motion option (as specified on the Boundary Details tab), or mesh regions that are used in such boundaries, may be selected.

##### 21.1.5.1.14. Aerodynamic Damping: [Aerodynamic Damping Name]: Integration Multiplier

Enter an integer that multiplies with the period of mesh motion to yield the Integration Interval.

##### 21.1.5.1.15. Aerodynamic Damping: [Aerodynamic Damping Name]: Integration Interval

This is a read-only value indicating the size of the time interval over which integration is carried out as part of the aerodynamic damping calculation. It is equal to the period of mesh motion multiplied by the specified Integration Multiplier. The period of mesh motion is the inverse of the Frequency value specified on the Boundary Details tab (see Periodic Displacement in the CFX-Solver Modeling Guide) for the boundary over which integration is carried out as part of the aerodynamic damping calculation.

##### 21.1.5.1.16. Radiometer: Frame Overview

(applies only when using the Discrete Transfer or Monte Carlo thermal radiation model)

A radiometer is a user defined point in space that monitors the irradiation heat flux (not incident radiation) arriving at the required location. The user specification involves much more than just the location of the sensor, as it also requires the viewing direction, its temperature and some numerical controls for each particular sensor.

By default, radiometers are ideal and the efficiency factor is 1.

A cyan arrow with a cross-hair is used to denote the location of each sensor in the viewer.

For details, see Radiometers in the CFX-Solver Modeling Guide.

##### 21.1.5.1.17. Radiometer: List Box

This list box is used to select radiometer objects for editing or deletion. These objects can be created or deleted with the icons that appear beside the list box.

###### 21.1.5.1.17.1. Radiometer: [Radiometer Name]: Option

- Cartesian Coordinates

###### 21.1.5.1.17.2. Radiometer: [Radiometer Name]: Cartesian Coordinates

Enter Cartesian coordinates that describe the location of the radiometer. These coordinates are interpreted in the coordinate frame associated with the radiometer. For details, see Coordinate Frames and also Coordinate Frames in the CFX-Solver Modeling Guide.

###### 21.1.5.1.17.3. Radiometer: [Radiometer Name]: Temperature

Enter the temperature of the radiometer.

###### 21.1.5.1.17.4. Radiometer: [Radiometer Name]: Quadrature Points

Enter the number of rays used for ray tracing from the radiometer.

###### 21.1.5.1.17.5. Radiometer: [Radiometer Name]: Coordinate Frame Check Box

This check box determines whether the coordinate frame used to interpret the location and direction specifications of the radiometer will be specified or left at the default of `Coord 0`.

###### 21.1.5.1.17.6. Radiometer: [Radiometer Name]: Coordinate Frame Check Box: Coordinate Frame

Select a coordinate frame to interpret location and direction specifications of the radiometer. For details, see Coordinate Frames and also Coordinate Frames in the CFX-Solver Modeling Guide.

###### 21.1.5.1.17.7. Radiometer: [Radiometer Name]: Diagnostic Output Level Check Box

This check box determines whether the diagnostic output level will be specified or left at the default of 0.

###### 21.1.5.1.17.8. Radiometer: [Radiometer Name]: Diagnostic Output Level Check Box: Diagnostic Output Level

Enter a number greater than zero. The CFX-Solver will write the ray traces to a series of polylines in a `.csv` file that can be visualized in CFD-Post. This can be used to determine if the number of quadrature points is optimal. For details, see Radiometers in the CFX-Solver Modeling Guide.

###### 21.1.5.1.17.9. Radiometer: [Radiometer Name]: Direction: Option

- Cartesian Components

###### 21.1.5.1.17.10. Radiometer: [Radiometer Name]: Direction: X Component, Y Component, Z Component

(applies only when Monitor Objects check box: Radiometer: [Radiometer Name]: Direction: Option is set to `Cartesian Components`)

Enter a numerical quantity or CEL expression for each Cartesian component of a direction vector that represents the orientation of the radiometer.

##### 21.1.5.1.18. Monitor Surfaces: Frame Overview

Monitor Surfaces are defined on 2D User Locations (see Importing a User Surface into CFX-Pre) and can be used for monitoring and post-processing selected variables at the User Surface location in ANSYS CFD-Post.

Monitor surfaces can be used to observe the solution at a Monitor Surface location while the solver is in progress (see Monitor Run in Progress in the CFD-Post User's Guide).

Additionally, by specifying output variables on the surface but selecting `None` on the Results tab the amount of data written to solver results files can be reduced. For details, see the Option setting for the Results tab.

Note: Monitor surfaces (and by extension live monitoring of solutions in CFD-Post) is not supported for Transient Blade Row cases or ANSYS Workbench.

Note: Monitor Surfaces are always defined in the stationary frame of reference and cannot move relative to any frame of reference, or with any rotating domain.

##### 21.1.5.1.19. Monitor Surfaces: List Box

This list box is used to select Monitor Surface objects for editing or deletion. Monitor Surface objects can be created or deleted with the icons that appear beside the list box.

###### 21.1.5.1.19.1. Monitor Surfaces: [Monitor Surface Name]: Option

Only User Locations can be used to define a Monitor Surface.

###### 21.1.5.1.19.2. Monitor Surfaces: [Monitor Surface Name]: Coordinate Frame

Select a coordinate frame to define the Monitor Surface in. To create a new coordinate frame, see Creating a New Coordinate Frame. By specifying a coordinate frame that rotates, the monitor surface will effectively remain stationary relative to that frame, and rotate relative to the global frame. This enables simpler live monitoring and post-processing for cases with rotating domains.

###### 21.1.5.1.19.3. Monitor Surfaces: [Monitor Surface Name]: Output Variables List

See Output Variables List.

Select the output variables to write to the results file at the Monitor Surface location. Conservative values for these variables will be interpolated from the volume data onto the Monitor Surface.

###### 21.1.5.1.19.4. Monitor Surfaces: [Monitor Surface Name]: Output Location List

Choose the User Location to write solution data from.

###### 21.1.5.1.19.5. Monitor Surfaces: [Monitor Surface Name]: File Compression Level

See File Compression.

###### 21.1.5.1.19.6. Monitor Surfaces: [Monitor Surface Name]: Output Frequency

See Output Frequency Options.

##### 21.1.5.1.20. Monitor Surfaces: Monitor Location Data Retention

This behaves in the same way as the Backup Data Retention option on the Backup tab but only applies to monitor location data files.

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