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Inlet velocity profile for turbulent pipe flow using swak4Foam

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Inlet velocity profile for turbulent pipe flow using swak4Foam

Posted September 14, 2017 at 06:29 by kindle

This is for the outer layer PowerLaw

Quote:
Originally Posted by zordiack View Post
Hi, I wanted a fully developed inlet velocity profile for my 3D-case and I decided to implement it using swak4Foam since I couldn't figure out how to do it with native OpenFOAM tools. So, I thought I'd share my solution here since it took me a while to figure it out.

Please note that in my case the inlet pipe centerline run along the y-axis, but it should by easy enough to modify for other cases too. Turbulent velocity profile is calculated using the power law formulation.

Code:
        pipe_inlet
        {
              type groovyBC;
              value uniform (0 0 0);
              variables (
                "n=7;"  //power law coefficient n
                "d=0.125;"  //pipe diameter
                "volFlowRate=0.1;"  //volumetric flow rate
                "Umean=volFlowRate/(pi*pow((d/2),2));"   //calculate mean velocity
                "Umax=Umean*(((n+1)*(2*n+1))/(2*pow(n,2)));"  //calculate max velocity
                "profile=Umax*pow(1-sqrt(pow(pos().x,2)+pow(pos().z,2))/(d/2),(1/n));"
                //calcucate power law velocity profile Umax*(1-r/R)^(1/n)
                );
              valueExpression "normal()*-profile";
              //apply to boundary, normal() is surface normal vector and minus is needed for inflow
        }
I hope someone finds this useful

PS: swak4Foam development version compiles for OpenFOAM-2.3.x and at least groovyBC is working fine
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