# Volume Fraction, profile data problem

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 August 18, 2009, 07:34 Volume Fraction, profile data problem #1 Member   Join Date: Aug 2009 Posts: 42 Rep Power: 9 Hi, I´m simulating waves using profile data at the inlet. As I have experimental data from the height of the wave vs time, I used a profile data containing x,y,z and volume fraction as columnes. The results aren´t correct. x and y are fixed values (the point where the height of the wave is measured). I have put x as the time and y = 0 all time. z is the mesured height. Volume Fraction values are 1 or 0 depending on the value of z (positive or negative) The expression: Filename.Volume Fraction((t*1[s^-1]*1[m]),y,z) It doesn´t work!!! Would kindly anyone tell me what could be wrong? Thank you very much in advance Cfxmar

 August 18, 2009, 18:25 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 12,704 Rep Power: 98 I think a 1D interpolation function would be more appropriate than the 3D one you are using. Try that. Glenn Horrocks

 August 19, 2009, 04:39 #3 Member   Join Date: Aug 2009 Posts: 42 Rep Power: 9 Thank you, Glenn. I have tried that but as the problem is 3D, the profile data needs three columns for x,y,z and one for the volume fraction. CFX doesn´t let me load the profile data file with only 2 columns (one for x as the time and one for the volune fraction)

 August 19, 2009, 04:47 #4 Senior Member   Lance Join Date: Mar 2009 Posts: 598 Rep Power: 12 I just did the same thing, but for a measured mass flow rate instead and a 1D profile data function worked fine for me. Looks like: FUNCTION: MassFlowInlet Argument Units = [m] Extend Max = true Extend Min = true File Name = massflow.csv Option = Profile Data Spatial Fields = X DATA FIELD: Mass Flow Rate Field Name = Mass Flow Rate Result Units = [kg s^-1] END END and the boundary condition: BOUNDARY: inlet Boundary Type = INLET Location = F18.16 BOUNDARY CONDITIONS: FLOW DIRECTION: Option = Normal to Boundary Condition END FLOW REGIME: Option = Subsonic END MASS AND MOMENTUM: Mass Flow Rate = MassFlowInlet.Mass Flow Rate(FT) Option = Mass Flow Rate END TURBULENCE: Option = Low Intensity and Eddy Viscosity Ratio END END END where FT is defined as FT = 1[m/s]*t Lance

 August 19, 2009, 05:45 #5 Member   Join Date: Aug 2009 Posts: 42 Rep Power: 9 Thank you very much, Glenn and Lance. I´m running the simulation, tomorrow I will see the results. Cfxmar

August 19, 2009, 08:09
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Glenn Horrocks
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Posts: 12,704
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Quote:
 I have tried that but as the problem is 3D, the profile data needs three columns for x,y,z and one for the volume fraction. CFX doesn´t let me load the profile data file with only 2 columns (one for x as the time and one for the volune fraction)
Come on, think outside the square.... You don't need a whole variable field to store the volume fraction. It can be stored as a single number (that is the height of the surface at that time) and the volume fraction field can be evaluated for height from that using a simple CEL step or if function. Now you can use a 1D interpolation function.

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