[Wingman]

I am using Fluent to find Lift, Drag, Moment, Pressure Coeff etc. of an airfoil. The airfoil is small and the reynolds number is low (1 > 0.1 > M) so I'm assuming incompressible flow.

I'm using a pressure based solver and Velocity Inlet and Pressure Outlet boundary conditions. When changing the angle of attack the flow exits the domain at the Velocity inlet and I need to ensure that overall continuity is maintained in the fluid. How can I check?

Originally Posted by 7.4.3 Calculation Procedure at Velocity Inlet Boundaries

Sometimes a velocity inlet boundary is used where flow exits the physical domain. This approach might be used, for example, when the flow rate through one exit of the domain is known or is to be imposed on the model.

In such cases you must ensure that overall continuity is maintained in the domain.

In the pressure-based solver, when flow exits the domain through a velocity inlet boundary FLUENT uses the boundary condition value for the velocity component normal to the exit flow area. It does not use any other boundary conditions that you have input. Instead, all flow conditions except the normal velocity component are assumed to be those of the upstream cell.

[Antanas]

Originally Posted by Wingman

I am using Fluent to find Lift, Drag, Moment, Pressure Coeff etc. of an airfoil. The airfoil is small and the reynolds number is low (1 > 0.1 > M) so I'm assuming incompressible flow.

I'm using a pressure based solver and Velocity Inlet and Pressure Outlet boundary conditions. When changing the angle of attack the flow exits the domain at the Velocity inlet and I need to ensure that overall continuity is maintained in the fluid. How can I check?

As far as I remember in Fluent you should calculate mass flow rate through your boundaries and make sure net flux is almost 0 (Postprocessing → Reports → Fluxes...).

[Wingman]

Originally Posted by Antanas

As far as I remember in Fluent you should calculate mass flow rate through your boundaries and make sure net flux is almost 0 (Postprocessing → Reports → Fluxes...).

You are correct. Thanks!

inlet: 582.45357
outlet: -582.45357
Net -4.7293724e-09