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August 24, 2010, 18:35 |
Pressure boundary condition
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#1 |
Senior Member
Join Date: Nov 2009
Location: Michigan
Posts: 135
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For a problem like laminar flow in a lid driven cavity, we specify the pressure boundary condition as dp/dn = 0. How do we arrive at this boundary condition?
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August 24, 2010, 19:14 |
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#2 |
New Member
César Vecchio
Join Date: Jul 2010
Location: Córdoba, Argentina
Posts: 21
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I guess it's like one of Prandlt's boundary layer deductions, stattic pressure doesn't change with height (the normal), that's what the zero derivative means, no change. However, I don't recall well the cavity case.
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August 25, 2010, 02:54 |
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#3 |
Senior Member
Hamid Zoka
Join Date: Nov 2009
Posts: 282
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the pressure gradient across the boundary layer is zero.
it means the pressure inside the boundary layer is equal to that outside the boundary layer. therefore when you are to solve viscous flow passing a wall, pressure condition will be in fact the zero gradient pressure normal to wall. regards |
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August 25, 2010, 07:36 |
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#4 |
New Member
CCTech
Join Date: Jul 2010
Posts: 20
Rep Power: 15 |
HI
Since the boundary layer thickness is small, it is assumed that within the boundary layer free stream pressure is impressed upon. Hence dp/dn normal to the wall is considered negligible and can be ignored. Thanks CCTech Pune |
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