simple question on pressure boundary condition

Hooman · December 4, 2015, 12:13

At walls, were velocity is zero, is the normal pressure gradient always equal to zero or is that for incompressible flows?

FMDenaro · December 4, 2015, 12:56

Quote:

Originally Posted by Hooman

At walls, were velocity is zero, is the normal pressure gradient always equal to zero or is that for incompressible flows?

the normal component of the pressure gradient evalated at the wall is never exactly zero ... the Prandtl theory for the BL shows it is of order (1/Re)

Hooman · December 4, 2015, 13:36

Is it set to zero in simulations?
In particular laminar flows?

FMDenaro · December 4, 2015, 13:58

Quote:

Originally Posted by Hooman

Is it set to zero in simulations?
In particular laminar flows?

setting dp/dn = 0 is an approximation, it would imply that

dvn/dt = n.(diffusion - convection)

December 4, 2015, 12:13	simple question on pressure boundary condition	#1
Hooman Senior Member Join Date: Jun 2010 Posts: 111 Rep Power: 15	At walls, were velocity is zero, is the normal pressure gradient always equal to zero or is that for incompressible flows?

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December 4, 2015, 13:36		#3
Hooman Senior Member Join Date: Jun 2010 Posts: 111 Rep Power: 15	Is it set to zero in simulations? In particular laminar flows?