Hi Siamak,

RMS of velocity fluctuation are identified as rms velocity and they appear in post-processing menu only if you have had turned "sample data" on, in the calculate panel.

Could you post a screenshot of this so-called RSME parameter?

Regards

Hi Ehsan,

Actually, my question is how does FLUENT define and calculate RSME?

Thanks,

OK, firstly you have indicated "RSME" in your original question and it has changed to "RMSE" in your last post. Which version of ANSYS Fluent are you using? I could not find this parameter in version 15.0 manual. So, I suppose it is the same rms fluctuation parameter as described in your original question.

Here we have:

Ubar-->Mean (time-averaged) velocity

u_n-->instantaneous velocity at nth time-step

uPrime_n=u_n-Ubar-->instantaneous velocity fluctuation at nth time-step

u_rms=SQRT(1/n*(uPrime_1^2+uPrime_2^2+...+uPrime_n^2))

This is how rms fluctuations are calculated.

Regards,

Ehsan

Thanks, can we say the RSME in Y direction is equal to the mean square root of the normal stress in Y direction?

(I am using ANSYS 18)

Yes, y-velocity rms (not RSME!) is the square root of Normal Reynolds stress component .

Regards,

Ehsan

Hi Sir. I would like to know if you have solved your problem (getting RMS velocities components in newer version FLUENT). Apparently, I can only obtain RMSE values in my FLUENT 16.2. Do you have any idea on how to get RMS values in newer version or if there is any method to convert RMSE values to RMS values?