Define the Physics

Define the physics conditions applied to the model.

You use physics specifications to define optional features of a fluid flow simulation, like the energy transport equation, turbulence model, volume of fluid model parameters, and thermal effects. You use steady-state steps to perform a fluid dynamic analysis on a stationary system. When you use a steady-state flow step, you can specify general options, such as the maximum number of iterations and the error threshold.

In this example, you create two physics behavior specifications. The first is for the fluid and includes thermal effects and a realizable k-epsilon turbulence model. Using a turbulence model allows for a more realistic simulation of air flow through the CPU board. The second is for the solid and includes only thermal effects. You then create a steady-state step that represents steady air flow during the simulation.

  1. From the Setup section of the action bar, click Scenario .
    The model opens in Fluid Scenario Creation.
  2. From the Procedures section of the action bar, click Physics Behavior .
  3. Select Fluid as the physics state.
  4. Select Enable thermal effects.
  5. Select Realizable k-epsilon as the turbulence model.
  6. Accept the default parameters for this turbulence model.
  7. Click OK.
  8. From the Procedures section of the action bar, click Physics Behavior .
  9. Accept the default parameters, and click OK.
    The thermal effects for the solid physics are enabled.
  10. From the Procedures section of the action bar, click Steady State Step .
  11. Enter a maximum iteration of 2000 and an error threshold of 1%.
  12. Click OK.