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-   -   Plotting boundary layer thickness along x coordinate, general thoughts (http://www.cfd-online.com/Forums/main/118871-plotting-boundary-layer-thickness-along-x-coordinate-general-thoughts.html)

mix June 5, 2013 14:05

Plotting boundary layer thickness along x coordinate, general thoughts
 
Hey everyone,

currently, I'm working on my masters thesis. I do now have a problem, which is related to boundary layer growth on a flat plate.
I would like to plot the boundary layer thickness calculated by the code along the streamwise coordinate to compare boundary conditions in order to simulate bl suction (see the image attatched).
There are formulae to calculate the thickness of a turbulent bl on a flat plate, but the single variable given in these equations is the x coordinate infuencing the coordinate based reynolds number. as I will have a suction patch somewhere "down the road", which will influnce bl growth and thickness, this method is unrewarding yet not ... the actual bl calculated by the cfd code.
I hope you guys do have some ideas on that topic as I am going nuts not finding a proper solution.


Greetings

http://imageshack.us/a/img9/1811/blgrowth.png

mettler June 5, 2013 15:50

just out of curiosity, what velocity are you using for the local Re at your suction?

mix June 5, 2013 16:53

The suction volocity in negative y direction ist 0.1*freestream velocity, if you mean this. This is a value taken from literature.

Aeronautics El. K. June 8, 2013 17:01

Hi Michael.

May I ask why you made this schematic the way you did? I mean, it looks as if there is a flow before the suction patch - a flow that's totally sucked by the patch - and another flow just after it. Will the suction patch be big or powerful enough so as to suck the whole flow in that region?

mix June 9, 2013 10:15

No the bl won't be sucked in completely. The schematic was a quick drawing with powerpoint to show what I want to plot: The reduction of bl thickness by the suction. There will be a constant flow over the patch.


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