Velocity Inlet Boundary condition in LES
 

Dear Foamers

As I know, there are numerous methods for implementing velocity inlet B.C. in OpenFOAM for LES.

Methods like precursor simulation, Random Inflow and Recycling method (Mapped Velocity from downstream).

At the beginning I used precursor type i.e. extended the inlet B.C. of the jet to the upstream pipe and used fixed value for the velocity quantity. However, this approach resulted in increased velocity profiles in the domain (a Bluff-body stabilized flame)

The Diameter of the bluff-body is 50 mm and I have extended the flow to the upstream in pipe flow about 50 mm i.e. same value with the Bluff-body diameter.

At the moment I have omitted the upstream extension and modelled the computational domain from the beginning of the injection by using Random Inflow approach.

Would some body PLZ hint me why precursor method resulted in increased velocity profiles in the domain ? **Cause this method is in the accpetable methods. at least as I know.