problem with boundary layer
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Hello Foamer’s
I want to simulate Boundary Layer in Newtonian and viscoelastic Fluid on 2-D flat plate with openFoam 1.5 dev My geometry is 2D flat plate Width: 0.5 meter Long: 5 meter Uniform velocity: 1m/s Velocity BC’s Uperwall Type fixedvalue; Value uniform (1 0 0); Lowerwall Type fixedvalue; Value uniform (0 0 0); Inlet Type fixedvalue Value uniform (1 0 0); Outlet Type zeroGradient; Pressure BS’s Uperwall Type zeroGradient; Lowerwall Type zeroGradient; Inlet Type zeroGradient; Outlet Type fixedValue; Value uniform 0; I set zeroGradient boundary condition velocity for uperwall but got the similar result, After simulation we have velocity profile as below: According to boundary layer theory in anywhere velocity must lower or equal from uniform velocity We used icoFoam and ViscoelasticFluidFoam(Giesekus Model) but in the both in some point velocity more than uniform velocity. regards |
Hi
Mass flow must be maintained. If you are setting a uniform inflow and also constraining the top boundary to a certain velocity, then it is normal to expect a higher vel somewhere in your domain. If you use a symmetryplane, this is alleviated, but could take a while/distance to stabilize. |
Hi
Thanks Gonpe is The boundary conditions like the atmosphere there? For velocity and pressure to flow out and nowhere hasn't more velocity than uniform flow velocity Thanks |
Quote:
cheers Saba |
Sorry for the late reply. Saba has re-iterated my earlier point ... thanks.
Just a last point. If you place a symmetry condition at the top of the domain, this will allow the speed to fluctuate along the top boundary. Of course, this turns the problem into one of bounded channel flow. In this case, the speed should be highest at the upper boundary. Goncalo |
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