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boundary condition problem for Free and porous media flow

Posted Oct 20, 2011, 12:52 p.m. EDT Fluid & Heat Version 4.1 1 Reply

Pavel Polyakov
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Hi, I am trying to simulate fluid flow (Free and porous media flow) in the rectangular geometry. At the boundary i need to specify the gradient of velocity (not the velocity by itself, that can be easily done by choosing the option 'wall' (slip no slip, moving wall ect ...)). I did not find the possibility to put the gradient of velocity instead of velocity as the boundary condition. Thanks.
1 Reply Last Post Oct 20, 2011, 2:53 p.m. EDT
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Oct 20, 2011, 2:53 p.m. EDT
It is not common to have a boundary condition specifying just the gradient of the velocity in free flow. Even then you cannot use the whole velocity gradient tensor but only the normal projection of that gradient. Can you use the Boundary Stress condition instead? It is the closest “Neumann” boundary condition that involves velocity gradients.

Nagi Elabbasi
Veryst Engineering
It is not common to have a boundary condition specifying just the gradient of the velocity in free flow. Even then you cannot use the whole velocity gradient tensor but only the normal projection of that gradient. Can you use the Boundary Stress condition instead? It is the closest “Neumann” boundary condition that involves velocity gradients. Nagi Elabbasi Veryst Engineering

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