Fluids

Fluids

function expression

    • aar007
      Subscriber

      Hi, I  am trying to write a Function expression but can't input the value axis of z to get the velocity profile = uref(z/zref)^alpha.


       get the error (error at host invalid expression uref(z/zref)^alpha the fluent processor could not be started.


      the z is from the scroll down when I type letter z


      I want the z to be in the z-axis. 

    • aar007
      Subscriber

      using fluent 19.4


       

    • Karthik R
      Administrator

      Hello,


      Could you please try something like this?


      uref [m s^-1] * (z / z_ref [m]) ** alpha


      Please see the screenshot.


      Here uref = 0.2, z stands for the z-coordinate, ** is an operator for (power), and alpha = 2



      Hope this helps.


      Thanks.


      Karthik

    • aar007
      Subscriber

      it works but when I try computing my inlet conditions in reference value I get *nan* in velocity section. a picture of my domain and coordinates


      my domain

    • aar007
      Subscriber

      my inlet is at x=-1 using the magnitude and direction option under velocity specification method

    • Karthik R
      Administrator

      Hello,


      Can you send me the exact formula you are using? And also elaborate on what you would like to see here?


      Thank you.


      Best,


      Karthik

    • aar007
      Subscriber

      used the same formula in your first reply. uref [m s^-1] * (z / z_ref [m]) ** alpha. my issue in the reference values. i hope this is clear enough.


    • DrAmine
      Ansys Employee
      That is not a big deal: just input an average velocity in the reference values.
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