Node258 - CFD SUPPORT

Previous: Test case description Up: Test case: External Aerodynamics Next: The Flow around the
This is an automatically generated documentation by LaTeX2HTML utility. In case of any issue, please, contact us at info@cfdsupport.com.

Parabolic velocity profile in boundary layer

Assuming parabolic profile in boundary layer one should create an inlet boundary condition according to those assumptions.
One can use standard boundary condition of the type fixedValue and our custom utility setVelocityProfile computes the nonuniform velocity distribution at the inlet.
The equation of velocity parabolic profile in boundary layer is derived from Navier-Stokes equations,

Here is the boundary layer thickness and is the velocity of the main stream.

Figure: Parabolic profile

Utility setVelocityProfile sets the parabolic velocity profile at the inlet patch

The velocity profile represents the boundary layer with respect to the equation

   double Umain = Upatch[patchi].x();
   
   forAll(faceCentres, facei)
   {
      double fcY = faceCentres[facei].y();

      if(fcY <= L) 
         Upatch[facei].x() = (2.0*Umain/(L*L))*(L*fcY-0.5*fcY*fcY);
      else
         Upatch[facei].x() = Umain;
   }

The source code of the utility is present in the training materials in folder setVelocity.
Copy utility folder and compile it using wmake:
# mkdir -p $WM_PROJECT_USER_DIR/applications/utilities
# cp -r .../training/applications/utilities/setVelocity \ $WM_PROJECT_USER_DIR/applications/utilities/
# cd $WM_PROJECT_USER_DIR/applications/utilities/setVelocity
# wmake
After a successful compilation the utility can be run from the root directory of any test case using the command setVelocityProfile.