### 1.10.2. Solid Time Scale Estimate

The solid time scale estimate will, in general, be much larger than the fluid time scale.

The length scale used to calculate a solid time scale, , is calculated in the same manner as for fluid time scales. The default value is taken as the cube root of the volume of the solid domain.

A volume averaged diffusion is calculated as:

| (1–273)

where each quantity is volume averaged over the solid. The solid time scale is finally calculated as:

| (1–274)

where is the specified solid timescale factor, which has a default value of 1.

When a rotating motion is enabled in a solid domain, the advective time scale is then computed as where is the angular velocity. The solid timestep is taken as the minimum between the diffusive and this new advective () timescale.

The value of the computed timestep size is recorded in the .out file.

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