Hi, could any one please tell me how to calculate limiting streamlines near the wall?

thanks in advance, srikanth

If there is no flow through the wall, the wall interface is the limiting streamline or surface of streamlines.

The velocity on a solid surface being zero, we cannot directly define streamlines on a solid surface. If "z" is the coordinate normal to the surface then the velocity is proportional to "z" very close to the surface and we can define the limiting streamlines as the limit as z->0 (continuity of the velocity field is assumed). They are also related to skin friction lines which are used to identify points of separation in a 3-D flow. See <a href=http://aerodyn.org/Wings/3dsepar.html>this</a> page and references therein.

Actually this point of view is no longer the current view of separation - a three-dimensional flow does not necessarily possess a nodal point at separation. Also in unsteady flows the separation point is not even situated at the wall. See the recent book by Sychev et al "Asymptotic theory of separated flows" (Cambridge university press).

To obtain the limiting streamlines you simply calculate the surface values of the stress and use the (in) surface components as "velocities" in the calculation of the streamlines.

thank you all for helping me in knowing about limiting streamlines....now Iam using the surface stress components as velocities in the calculation of streamlines...

[potentialFoam]

Dear Foamers,


took me quite a while to find a way how to plot 'limiting streamlines'. Thanks to the participants in this thread, especially Tom, for providing information and a how-to.


I just would like to add this
https://mycourses.aalto.fi/pluginfil...e_openfoam.pdf
(see page pp. 15)

because it helped me a lot - hopefully you can also benefit! First, I thought this thread might be too old to provide a proper answer...


Regards