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KKA August 28, 2004 00:13

YPLUS IN CFX5.7-Draft Tube
hi guys

I am doing some runs on draft tube using CFX5.7. The orientation of the geometry is such that the Z-axis is perpendiclar to the draft tube inlet, and the y-axis is in the direction of the elbow and the outlet. the spanwise direction which is the width is the x-axis.

Now, when I extracted my YPLUS values, they're in thousands. But I knew that my first node on the wall shdn't give me that value after I compute it from the wall shear stress. I don't know if CFX is taken the coresponding original y values realative to the origin or the the normal distance to the wall at respective wall.

Can somebody help me out. if you need more explaination, please do email me.

Thanks a lot

Guy August 28, 2004 12:55

Re: YPLUS IN CFX5.7-Draft Tube

CFX will return the value based on the normal distance from the wall. Two variables are output, Yplus and Solver Yplus. Yplus is calculated in the standard sense, based on the distance to the first node. "Solver Yplus" is what is actually used by the turbulence model (considering the scalable wall functions).

There isn't much room for error in the CFX calculation, so I would check yours.


KKA August 28, 2004 16:22

Re: YPLUS IN CFX5.7-Draft Tube
okay thanks. I'll give it a shot again.


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