SimScale CAE Forum

Dynamic Pressure


#1

Hey everyone!

Just had a quick question in general, what does dynamic pressure means at a wall. As I most of the time provide wall BC as no-slip, so the velocity being zero at the wall how can I have dynamic pressure at the wall.

Does it takes values from the adjacent cell and compute or something!! Just a guess…

Thanks in advance!

Om


#2

Yes a no slip wall has 0 velocity at the surface but it still has a dynamic pressure from all those other air particles around the stationary ones that are stuck to the surface and the continually adding up of dynamic forces all the way through the boundary and into the freestream (and beyond :wink: )…


#3

Yes @DaleKramer !! Thats what I was thinking…

But if I go for structural analysis by using the data that I got from my CFD simulation of Total pressure, Static Pressure, and Dynamic Pressure.

Then how does using dynamics pressure at wall make sense!! As at the wall V=0 and dynamic pressure in due to the surrounding elements so it’s acting in surrounding not particularly at the wall. ( And in structure I am just concerned about the pressure acting on the wall)

:sweat_smile::sweat_smile:
I guess I am missing something over here!!


#4

I believe that dynamic pressure vector ‘direction’ at the wall is perpendicular to the wall, the force on the wall in the parallel direction, results from wall shear stresses. That should not be too hard to visualize/use for FEA purposes but I have little experience there…