Boundary Layer

Jing_min · February 21, 2012, 09:39

Hi
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)

Thanks!!!

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.

February 21, 2012, 09:39	Boundary Layer	#1
Jing_min New Member Jing Join Date: Dec 2011 Posts: 20 Rep Power: 15	Hi 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) Thanks!!!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[snappyHexMesh] No layers in a small gap	bobburnquist	OpenFOAM Meshing & Mesh Conversion	6	August 26, 2015 10:38
Grid Independence of Boundary layer	Luigi_	Main CFD Forum	0	December 14, 2011 14:42
Boundary Layer Question	scottneh	STAR-CCM+	3	September 30, 2010 15:21
3D Boundary Layer	Mario	FLUENT	0	February 17, 2009 04:40
[Commercial meshers] Trimmed cell and embedded refinement mesh conversion issues	michele	OpenFOAM Meshing & Mesh Conversion	2	July 15, 2005 05:15

February 21, 2012, 12:49		#2
JBurnham Senior Member Jeff Burnham Join Date: Apr 2010 Posts: 204 Rep Power: 17	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.