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Jing_min February 21, 2012 09:39

Boundary Layer
I use f3d 9.3.2. I have modeled a simple spillway. I want to know how to calculate the boundary layer thickness along the spillway?
(There is no output for that)


JBurnham February 21, 2012 12:49

You'll have to compare the velocity in each cell along the spillway surface to the free-stream velocity (or use the average velocity for the top few cells of flow). When the near-wall velocity reaches 99% of the free-stream velocity, that height above the wall is conventionally assumed to be the boundary layer thickness (e.g., Schlichting "Boundary Layer Theory"). The accuracy of the measurement will be on the order of the cell size. You could use a "neutral file" (see the manual) to specify a number of points and get velocity output for just those points.

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