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-   -   simulation of stokes boundary layerr (oscillating boundary layer) (https://www.cfd-online.com/Forums/fluent/95219-simulation-stokes-boundary-layerr-oscillating-boundary-layer.html)

 beguxa December 9, 2011 17:25

simulation of stokes boundary layerr (oscillating boundary layer)

Simulation objective - I am trying to simulate effect of oscillating free stream flow field on the boundary layer on a stationary flat plate using Fluent i.e. there is an externally induced oscillation in the free stream defined as:
dp/dx=A*cos(omega*t); A= constant;
It is quite similar to the stokes boundary layer problem where we have a oscillating far field imposing/affecting the boundary layer on a stationary flat plate. The Reynold's no (based on stokes boundary layer height) for my problem is 1790 (turbulent regime).

My trouble is - It has been several attempts, but the pressure gradient obtained by me from the RANS simulations is always smaller by the order of 2 than the theoretically imparted pressure gradient (dp/dx=A*cos(omega*t)). It would be a great help if you could please provide me with your views on following query:

1. I am "hooking" a momentum source term of 'A*cos(omega*t)' in the fluid as momentum source. Hope this approach is correct. Although I get the correct velocity field there are absolutely no pressure gradients present. Even the guage static pressure is zero. This is odd considering the velocity field, there should have been pressure gradients present. What is the best way to create the artificial pressure field in Fluent.

 beguxa December 10, 2011 05:30

no takers for this problem eh ! :)

what I am trying to do is : http://en.wikipedia.org/wiki/Stokes_boundary_layer

(second portion of oscillating far-field condition)

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