Bondary layer model

tlj · March 31, 2009, 03:47

Hi everyone,
I need to change the expressions of the rms fluctuating velocities in the near wall region to account for the anisotropic nature of turbulence in the boudary layer. This modification will be implemented in the 'Random Walk Model' used to account for particles turbulent dispersion (option in the Discrete Phase Model).
Can anyone help me with this. Any suggestions or macros I can use???
Thank you in advance.

HenrikS · March 31, 2009, 09:26

I have thought about this issue too, but never came around to do anything about it. You could either implement a random walk model on your own (probably what I would do), but that could be quite time consuming I guess. There is something called p->V_prime that I suspect could contain the fluctuating velocity components, and p->eddy_time that I suspect could contain the eddy life time or maybe rather the eddy interaction time. It would be nice if anyone with insight could comment on this? :-)

tlj · March 31, 2009, 14:45

Thanks a lot Henriks for your reply!

vincenzolights · June 23, 2021, 11:02

Hello everyone,
I'm trying to modify the DRW varying the V_prime and the eddy_time. A PhD thesis found on the internet shows the use of DEFINE_DPM_DRAG modifying directly p->eddy_time and V_prime but I'm not completely sure that it works fine because I tried to follow its path without success. In particular, I only need to modify correctly the eddy lifetime of particles.

Has someone in this forum customized successfully the DRW through UDF?

Thank you very much,
Vincenzo

March 31, 2009, 03:47	Bondary layer model	#1
tlj New Member Join Date: Mar 2009 Posts: 2 Rep Power: 0	Hi everyone, I need to change the expressions of the rms fluctuating velocities in the near wall region to account for the anisotropic nature of turbulence in the boudary layer. This modification will be implemented in the 'Random Walk Model' used to account for particles turbulent dispersion (option in the Discrete Phase Model). Can anyone help me with this. Any suggestions or macros I can use??? Thank you in advance.

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March 31, 2009, 09:26		#2
HenrikS Member Henrik Ström Join Date: Mar 2009 Posts: 33 Rep Power: 17	I have thought about this issue too, but never came around to do anything about it. You could either implement a random walk model on your own (probably what I would do), but that could be quite time consuming I guess. There is something called p->V_prime that I suspect could contain the fluctuating velocity components, and p->eddy_time that I suspect could contain the eddy life time or maybe rather the eddy interaction time. It would be nice if anyone with insight could comment on this? :-)

March 31, 2009, 14:45		#3
tlj New Member Join Date: Mar 2009 Posts: 2 Rep Power: 0	Thanks a lot Henriks for your reply!

June 23, 2021, 11:02		#4
vincenzolights New Member Vincenzo Luci Join Date: Jan 2019 Posts: 9 Rep Power: 7	Hello everyone, I'm trying to modify the DRW varying the V_prime and the eddy_time. A PhD thesis found on the internet shows the use of DEFINE_DPM_DRAG modifying directly p->eddy_time and V_prime but I'm not completely sure that it works fine because I tried to follow its path without success. In particular, I only need to modify correctly the eddy lifetime of particles. Has someone in this forum customized successfully the DRW through UDF? Thank you very much, Vincenzo