Froude Number CFX
hi,
Could anyone help me to determine Froude Number using CEL in CFX, Fn=V/sqrt(g*l). my problem is that Im working on a multiphase (water+air) flow over an obstacle and i dont know the fluid depth (water) what length scale should I consider and where could I find this specific variable? 
The length scale depends on what you are doing. For instance a ship is the length of the ship, wave models use the depth of water. So what are you modelling?

1 Attachment(s)
Quote:
Fn=V/sqrt(g*l). Table 3. Domain Physics for CFX Domain  Default Domain Type Fluid Location Primitive 3D Materials Air at 25 C Fluid Definition Material Library Morphology Continuous Fluid Water Fluid Definition Material Library Morphology Continuous Fluid Settings Buoyancy Model Buoyant Buoyancy Reference Density DenRef Gravity X Component 0.0000e+00 [m s^2] Gravity Y Component g Gravity Z Component 0.0000e+00 [m s^2] Buoyancy Reference Location Automatic Domain Motion Stationary Reference Pressure 1.0000e+00 [atm] Heat Transfer Model Isothermal Fluid Temperature 2.5000e+01 [C] Homogeneous Model True Turbulence Model k epsilon Turbulent Wall Functions Scalable Table 4. Boundary Physics for CFX Domain Boundaries Default Domain Boundary  inflow Type INLET Location INFLOW Settings Flow Regime Subsonic Mass And Momentum Normal Speed Normal Speed 2.6000e01 [m s^1] Turbulence Intensity and Length Scale Eddy Length Scale UpH Fractional Intensity 5.0000e02 Fluid Air Volume Fraction Value Volume Fraction UpVFAir Fluid Water Volume Fraction Value Volume Fraction UpVFWater Boundary  top Type OPENING Location TOP Settings Flow Regime Subsonic Mass And Momentum Entrainment Relative Pressure 0.0000e+00 [Pa] Turbulence Zero Gradient Fluid Air Volume Fraction Value Volume Fraction 1.0000e+00 Fluid Water Volume Fraction Value Volume Fraction 0.0000e+00 Boundary  outflow Type OUTLET Location OUTFLOW Settings Flow Regime Subsonic Mass And Momentum Static Pressure Relative Pressure DownPres Boundary  back Type SYMMETRY Location BACK Settings Boundary  front Type SYMMETRY Location FRONT Settings Boundary  bottom Type WALL Location BOTTOM3, BOTTOM1, BOTTOM2 Settings Mass And Momentum No Slip Wall Wall Roughness Smooth Wall 
Probably the easiest way to get the depth is to define a tall, thin rectangular region from the bottom to the top of your domain. Then if you do something like volumeInt(Volume Fraction)@region/volume()@Region this will give you a percentage height of the column in your region.
You will need to do a small edit to your mesh to do this. 
All times are GMT 4. The time now is 07:34. 