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
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.
I hope someone finds this useful 
PS: swak4Foam development version compiles for OpenFOAM-2.3.x and at least groovyBC is working fine
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
}
PS: swak4Foam development version compiles for OpenFOAM-2.3.x and at least groovyBC is working fine
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