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-   -   Oscillatory inlet velocity profile (http://www.cfd-online.com/Forums/openfoam/98424-oscillatory-inlet-velocity-profile.html)

alinve March 10, 2012 11:58

Oscillatory inlet velocity profile
 
Dear All,

I'm trying to validate openFoam to simulate oscillating flow fields.
I want to simulate 2D channel flow with oscillating inlet velocity. I'm using icoFoam as solver, the velocity inlet bc that I want to imposed is of the form u(t)=a+b*sin(2pi*f*t), where a, b are constant, t is time and the f is frequency of oscillation. Moreover I've imposed 0 pressure at the outlet and no-slip condition at the wall.
I'v tried to used the oscillatingFixedValue as boundary condition type for inlet velocity. The solution doesn't seem to converge. Have you got any suggestion? Has somebody used oscillatingFixedValue bc before?
Is it proper to describe my inlet condition?

Thanks in advance.

calim_cfd March 10, 2012 14:20

Hi!

you say your solution doesnt seem to converve... but you're doing a transient solution... you should operate with low residuals, but it won't converge to say.. e-5, e-7.... at most i guess 1e-2 maybe 1e-3, unless it's a very shy transient case.. :rolleyes:

tfuwa April 3, 2012 00:25

Hi Alinve,

Glad to know someone doing similar research. I am thinking the inlet boundary condition for pressure is also essential for the oscillating flow simulation. Be noted that the velocity at out BC changes with time. Can you specify those BCs that were imposed in your case?

Quote:

Originally Posted by alinve (Post 348709)
Dear All,

I'm trying to validate openFoam to simulate oscillating flow fields.
I want to simulate 2D channel flow with oscillating inlet velocity. I'm using icoFoam as solver, the velocity inlet bc that I want to imposed is of the form u(t)=a+b*sin(2pi*f*t), where a, b are constant, t is time and the f is frequency of oscillation. Moreover I've imposed 0 pressure at the outlet and no-slip condition at the wall.
I'v tried to used the oscillatingFixedValue as boundary condition type for inlet velocity. The solution doesn't seem to converge. Have you got any suggestion? Has somebody used oscillatingFixedValue bc before?
Is it proper to describe my inlet condition?

Thanks in advance.



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