Reply To: Modify taueff
I still have a question to ask. I am trying to reporduce the results you guys published on Large-eddy simulation coupled with wall models for turbulent channel flows at high Reynolds numbers with a lattice Boltzmann method — Application to Coriolis mass flowmeter. And the following are part of my results. I have put the image URL below. I am having trouble with dealing the N=40 situation. I can’t get it right. I use the u_tau=0.05 from DNS to normalize the velocity profile. For spatial average, I used whole field instead of using a line in your paper. For temporal averge, I simply used the functions in SuperLatticeTimeAveraged3D. Buy the way, I think there seems to be an error in SuperLatticeTimeAveragedCrossCorrelationF3D.
This is the origin code:
output[iDim] = _sDataMN.getBlock(iCloc).get(input+1,iDim)-_sDataM.getBlock(iCloc).get(input+1,iDimM) *_sDataN.getBlock(iCloc).get(input+1,iDimN)/_ensembles/_ensembles;
I change to:
output[iDim] = (_sDataMN.getBlock(iCloc).get(input+1,iDim)-_sDataM.getBlock(iCloc).get(input+1,iDimM) *_sDataN.getBlock(iCloc).get(input+1,iDimN)/_ensembles)/_ensembles;
These are the u_tau I got. When N=10, it’s good. I also tested N=20, it’s also great. I know when the first point loacts in the buffer layer, things will get tricky. But for N=40, the u_tau I got are too small, and the velocity are large. I checked Netwon’s method, it acts fine.
But in your paper, the results seems, at least, not bad. So how you guys did it? How can I improve my results. It’s really important for me. It will be appreciated very much if you guys can teach me to solve my problem. Thank you.
Musker(N=10): u_tau = 0.046746047117067945
Power-law(N=10): u_tau = 0.04784589543819295
Musker(N=40): u_tau = 0.025056878722764415
Power-law(N=40): u_tau = 0.02708617517323956
Best regards.