How to extract phase-locked avergae of the flow field for a rotating machine?

allenfieldin · December 25, 2018, 22:11

Dear Foamers,

recently I am doing flow analysis for a rotating wind turbine. I want to get the phase-locked average of the flow inside and downstream the rotor to validate my numerical model.

The "phase-average" is similar to what we do in PIV or other experiments, i.e., after the flow being fully developed, for certain azimuth angle or rotation angle thita, the flow field are extracted for each rotation cycle and these information will be averaged over dozens of cycles.

I looked over threads talking about this in the forum:
Phase locked average in run time.
Unfortunately, there is actually no valuable clue therein.

I believe there are some tricks I didn't notice, because phase-locked average is a quite common analysis tool or concept for rotating flow.

I really appreciate someone could give a solution or even a hint on this for me. Thanks

Allen

zhutaihang · March 7, 2019, 09:58

Hi Allen,

I think probably the best way is to use the probes in controlDict/functions. You can specify the probe location as the whole computational domain (or some section plane) and use timeStart and timeInterval to specify the phase interval. You can use Matlab or other software to average these data to get phase averaged result and illustrate it. But it will be extremely costly for a large domain.

This is just an idea. I have not yet verified it.

Taihang

December 25, 2018, 22:11	How to extract phase-locked avergae of the flow field for a rotating machine?	#1
allenfieldin Member ALLEN Join Date: Aug 2014 Posts: 32 Rep Power: 11	Dear Foamers, recently I am doing flow analysis for a rotating wind turbine. I want to get the phase-locked average of the flow inside and downstream the rotor to validate my numerical model. The "phase-average" is similar to what we do in PIV or other experiments, i.e., after the flow being fully developed, for certain azimuth angle or rotation angle thita, the flow field are extracted for each rotation cycle and these information will be averaged over dozens of cycles. I looked over threads talking about this in the forum: Phase locked average in run time. Unfortunately, there is actually no valuable clue therein. I believe there are some tricks I didn't notice, because phase-locked average is a quite common analysis tool or concept for rotating flow. I really appreciate someone could give a solution or even a hint on this for me. Thanks Allen

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March 7, 2019, 09:58		#2
zhutaihang New Member Taihang Zhu Join Date: May 2018 Location: London Posts: 6 Rep Power: 7	Hi Allen, I think probably the best way is to use the probes in controlDict/functions. You can specify the probe location as the whole computational domain (or some section plane) and use timeStart and timeInterval to specify the phase interval. You can use Matlab or other software to average these data to get phase averaged result and illustrate it. But it will be extremely costly for a large domain. This is just an idea. I have not yet verified it. Taihang