RMS is missing?

heisenmech · March 22, 2019, 19:44

Hi,

I remember there used to be RMS option for unsteady statistics in FLUENT but I dont seem to find RMS, there is just RMSE. When I check the user/theory guide, it does still mention both RMS and RMSE.

Does anyone know why RMS is not available?

Thanks.

LuckyTran · March 23, 2019, 01:19

RMS has been corrected to RMSE. There's never been an RMS option, that was a typo and a bug. Before it said RMS but was actually calculating the RMSE. It has always calculated the RMSE and the interface has been updated to reflect that.

Well, it wasn't a bug per se. But a lot of people (like you) get it confused. It was presumed obvious that it is was the rms of the velocity fluctuations which is the rmse of the full velocity.

heisenmech · March 23, 2019, 16:19

Quote:

Originally Posted by LuckyTran

RMS has been corrected to RMSE. There's never been an RMS option, that was a typo and a bug. Before it said RMS but was actually calculating the RMSE. It has always calculated the RMSE and the interface has been updated to reflect that.

Well, it wasn't a bug per se. But a lot of people (like you) get it confused. It was presumed obvious that it is was the rms of the velocity fluctuations which is the rmse of the full velocity.

Thanks for the answer. Let me ask you one more question, just to make sure its all clear. If I want to calculate RMS of velocity fluctuation u' , I should use RMSE of instantaneous velocity u_ins. Right?

Thanks.

LuckyTran · March 25, 2019, 08:56

Right. rms of velocity fluctuation u' (which has 0 mean) is the same as the rmse of the instantaneous velocity u(t), which does not have 0 mean.

March 22, 2019, 19:44	RMS is missing?	#1
heisenmech Member Oguzhan Join Date: Aug 2017 Posts: 38 Rep Power: 9	Hi, I remember there used to be RMS option for unsteady statistics in FLUENT but I dont seem to find RMS, there is just RMSE. When I check the user/theory guide, it does still mention both RMS and RMSE. Does anyone know why RMS is not available? Thanks.

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March 23, 2019, 01:19		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,762 Rep Power: 66	RMS has been corrected to RMSE. There's never been an RMS option, that was a typo and a bug. Before it said RMS but was actually calculating the RMSE. It has always calculated the RMSE and the interface has been updated to reflect that. Well, it wasn't a bug per se. But a lot of people (like you) get it confused. It was presumed obvious that it is was the rms of the velocity fluctuations which is the rmse of the full velocity.

March 25, 2019, 08:56		#4
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,762 Rep Power: 66	Right. rms of velocity fluctuation u' (which has 0 mean) is the same as the rmse of the instantaneous velocity u(t), which does not have 0 mean.