Fluids

Fluids

RMS Values in RANS

    • krany3
      Subscriber

      I'm trying to check the rms vaules of the temperature in RANS. But, the rms temperature value is zero everywhere. Also, I don't see rms velocity in Fluent for RANS. How can see the rms velocity values? Why the rms temperature is zero ?

    • Keyur Kanade
      Ansys Employee

      Can you please give more information.


      What sampling interval you used? How did you plot rms values? Did you check global or auto range in contours?


      How many time steps you ran? what are input conditions?


      Please insert images also. 

    • krany3
      Subscriber

      The case that I ran was a steady case. The rms temperature value is zero and I don't see an option in Fluent to check the rms velocity values. 


      My inlet conditions are 300K temperature, modeled at atmospheric pressure and 2g/s mass flow rate.

    • Rob
      Ansys Employee

      What other boundaries did you add to alter the temperature? In R19 the steady statistics will be in the "Steady Statistics" part of the Fluent Post Processing: velocity & pressure look to be included in the statistics by default. 

    • krany3
      Subscriber

      I did not change any other variable. Since it's combustion, I provided the equivalence ratio of 0.67. I ran my simulations in R18.1. Will I be able to see the steady statistics if I open the case and data files in R19?

    • Rob
      Ansys Employee

      Not unless they're also recorded in R18.x   this is why we always recommend using the latest build: why learn on the older versions? 

    • krany3
      Subscriber

      I did not have the full academic version of R19. So, I had to use R18.1. 


      I've one more question. Fluent is displaying same contours for RMS and RMSE. When I tried to plot the RMS values in post processing, it plotted the same values as RMSE. What is the reason for not displaying the RMS values?

    • Rob
      Ansys Employee

      CFD Post doesn't always have all of the data available: Fluent only keeps some values in the .dat file, the rest are generated by the solver or not saved: otherwise the data files would be ridiculous sizes.  You can add data into the .dat file, and that's under File -> Data File Quantities from the top menu in Fluent. 

    • Keyur Kanade
      Ansys Employee

      Please check help manual. 


      29.12.4. Data Sampling for Steady State Statistics

    • Hadi96
      Subscriber

      Dear sir,


      i,m had done the vibration analysis , how could i get the RMS value, i had get the data , but it shown the negative graph, how could i get the RMS graph


    • Hadi96
      Subscriber

      Dear sir, 


      i,m had done the vibration analysis , how could i get the RMS value, i had get the data , but it shown the negative graph, how could i get the RMS graph


    • Rob
      Ansys Employee

      That's from Mechanical: please open a new thread to ask. 

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