Hi I need to calculate Y+ value for jet Impingement over flat plate

Nithyanandham · June 9, 2023, 02:25

CFDKareem · June 9, 2023, 13:49

Y+ is dependent on the shear stress at the wall which is in turn dependent on the velocity. For an impinging jet on a flat surface, your velocity will be 0 at the stagnation point, hit a maximum a few units out, and then taper off as the jet spreads over the plate. If your first cell height, delta Y, is consistent along the impingement surface then your Y+ will match the velocity. To confirm this you can plot a graph of the velocity over the same distance and you will see a similar curve.

You should use the maximum value of Y+ for you inquiry. Depending on the wall condition/solver you will want the Y+ number to be <1 everywhere in domain. The regions where Y+ is >1 may not be accurate.

There is no need to use some different formulation of Y+. The phenomena you are seeing is correct and is not due to the calculation of Y+.

Nithyanandham · June 12, 2023, 00:42

Thank you for your response.

June 9, 2023, 13:49		#2
CFDKareem Member Kareem Join Date: Nov 2022 Location: New York Posts: 90 Rep Power: 2	Y+ is dependent on the shear stress at the wall which is in turn dependent on the velocity. For an impinging jet on a flat surface, your velocity will be 0 at the stagnation point, hit a maximum a few units out, and then taper off as the jet spreads over the plate. If your first cell height, delta Y, is consistent along the impingement surface then your Y+ will match the velocity. To confirm this you can plot a graph of the velocity over the same distance and you will see a similar curve. You should use the maximum value of Y+ for you inquiry. Depending on the wall condition/solver you will want the Y+ number to be <1 everywhere in domain. The regions where Y+ is >1 may not be accurate. There is no need to use some different formulation of Y+. The phenomena you are seeing is correct and is not due to the calculation of Y+. Nithyanandham likes this. __________________ Please like the answer if it helped! Video Tutorials and Tips: https://www.youtube.com/@cfdkareem/featured

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June 12, 2023, 00:42		#3
Nithyanandham New Member G. Nithyanandham Join Date: May 2023 Posts: 3 Rep Power: 2	Thank you for your response.