Before you start a simulation, you must provide initial values for the solution variables under the Physics subsection of the control panel. This will assign values for flow, turbulence, or temperature variables in all of the control volumes within your computational mesh.
Click on Fluid Physics or Heat Transfer physics to view the Initialization settings.
The options available here depend on which physics you’ve selected.
Fluid Physics
For Fluid Physics, choose from the following in the Initialization dropdown menu:
Uniform Values: You will need to set Static Pressure, Velocity (as Cartesian components), and Temperature (for compressible flows). The flow initialization will then set uniform pressure, velocity, and temperature values throughout the domain.
Far-field Values: The flow initialization will set uniform pressure, velocity, and temperature values throughout the domain based on the static pressure, velocity, and temperature defined along your far-field boundary.
Potential Flow: A potential flow solution based on the Static Pressure and Temperature will be used to set initial values of uniform pressure, velocity and temperature throughout the domain.
Existing Solution: Select this to use a solution from within the same project. You will need to choose a simulation and an iteration from the dropdown menus. You can also interpolate from solutions in your project that used different meshes or geometry.
Notes:
When working with fully enclosed geometry, the average initial pressure is kept constant during the simulation.
Interpolating from transient moving grid cases is not currently supported.
Turbulence Model Initialization
Note: This option is available for Fluid Physics only.
If you are modeling turbulent flow, you must also initialize relevant variables for the turbulence model you are using.
If you are using Spalart-Allmaras, each of these will initialize the Spalart-Allmaras variable throughout the domain:
Turbulent Viscosity Ratio: This will calculate turbulent viscosity using the given ratio.
Turbulent Viscosity: This will calculate turbulent viscosity using the given value.
Uniform Value: This requires you to specify a Spalart-Allmaras variable.
Far-field Value: This will use the value set at your far-field boundary.
If you are using SST, each of these will initialize the turbulent viscosity and turbulence intensity throughout the domain:
Turbulent Viscosity Ratio and Intensity: This will use the turbulence intensity specified and calculate turbulent viscosity using the given ratio.
Turbulent Viscosity and Intensity: This will use the viscosity and intensity values you set in the boxes below.
Far-field Values: This will use the values set at your far-field boundary.
Heat Transfer Physics
For Heat Transfer in Solid physics, choose from the following in the Initialization dropdown menu:
Uniform Values: You will need to set an initial Temperature. This will set temperature values throughout the domain.
Existing Solution: Select this to use a solution from within the same project. You will need to choose a simulation and an iteration from the dropdown menus. You can also interpolate from simulations in your project that used different meshes, geometry, or simulations types (steady or transient).