2 Replies Latest reply on Nov 13, 2013 4:50 PM by Dan Hofstetter

    Service goals vs. user-defined goals

    Dan Hofstetter
    Dan Hofstetter Nov 11, 2013 4:36 PM

      I was told once that there are internal goals that Flow Simulation uses to determine if a calculation has converged or not, and that these can't be controlled by the user. 

      While messing around with the API, I came across "Service Goals" and think these may be those internal goals that I was told about. 

       

      The following Service Goals were listed for a study:

       

      dm/m

      Calculate_inc time/NC_Fluid

      Serv Press

      Serv Temp

      Serv Heatf

      Serv Mflow

      Serv MassFract0

      Serv MassFract1

      Serv MassFract2

      Serv MassFract3

      Serv MassFract4

       

      Does anyone know if these are actually being used internally for convergence?  If so, is there any point to defining Global Goals for Pressure and Temperature?  What about volume fraction of each fluid component?  If the mass fraction of each is already being monitored, it seems redundant.

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        • Re: Service goals vs. user-defined goals
          Jared Conway
          Jared Conway Nov 11, 2013 10:46 PM (in response to Dan Hofstetter)

          i'd get with your reseller and have them check with the developers on this one.

           

          if you wanted to test yourself, why not run a problem and compare those output the values and compare them?

           

          my gut feeling is that these aren't them because I don't think that the values that are monitored are things like pressures and temperatures, i think they are calculation residuales and some other stuff. but i don't remember the details.

            • Re: Service goals vs. user-defined goals
              Dan Hofstetter
              Dan Hofstetter Nov 13, 2013 4:50 PM (in response to Jared Conway)

              Great idea - thanks!  I ran a problem and added the available goals for comparison, here's what I found:

               

              ServPress = GGAvStaticPressure

              ServTemp = GGAvTemperature(Fluid)

              ServHeatf = most likely GGAvHeatFlux (I was running an adiabatic simulation, so the values were all zero)

              ServMflow = GGMassFlowRate

              ServMassFrac0 = GGAvMassFractionofAir (0 = first fluid or Air in my case, 1 = second fluid, etc...)

               

              The ones I am not sure about are 'dm/m' and 'Calculate_inctime/NC_Fluid'.

               

              At any rate, I don't know if it is really adding much fluff to the .FLD file to record the values of these if you add them to the simulation.  If they are of interest to you, it is worth adding them to the simulation since the service goals aren't easy to see without writing code to access the values.