Computational Domain

The Computational Domain is the region where the flow and heat transfer calculations are performed. When you create a new project, Flow Simulation automatically creates the Computational Domain enclosing the model. It is a rectangular parallelepiped for both the 3D analysis and 2D analysis and its boundaries are parallel to the Global Coordinate System planes.

For internal flows, the computational domain’s boundary planes automatically envelop either the entire model, if Conduction in solids is considered, or if Conduction in solids is not considered, the model’s flow passage only.

For external flows, the computational domain’s boundary planes are automatically distanced from the model:

• If the Fluid Flow option is disabled and the Conduction option is enabled the computational domain’s size in each direction (BCD,Xi) is defined as follows:

  	(1)

  where Dmodel,i is the geometry model size in each direction and Hmiddle is the average overall model size.

• If the Fluid Flow option is enabled and the flow velocity is not zero, the computational domain’s size in each direction (BCD,Xi) is defined as follows:

  	(2)

  where ei is component of the unit vector collinear to the flow velocity vector and Hmiddle is calculated as a projection to ei.

• If the fluid flow with natural convection is considered (the initial flow velocity is zero), the computational domain’s size in each direction (BCD,Xi) is defined as follows:

  	(3)

  where gi is component of the unit vector collinear to the gravity vector and Hmiddle is calculated according to the equation Equation 1.