[farzadmech]

Dear all
I want to simulate a water jet inside a water domain at T=25 Celsius. I have two problems(first one is not important at this time);
1- I use fvoptions to generate Ubar=jet velocity

momentumSource
{

    type            meanVelocityForce;

    active          on; //on;   

    meanVelocityForceCoeffs

    {
      timeStart   0.;
      duration    1000.;

        selectionMode   cellZone;       
        cellZone        CIRCLEinY;  

        fields                  (U);

        Ubar       (0.0 0.64 0.0) 

        relaxation  0.1;      
     
    }
}

When I use 0.64, it gives me almost double the value(2*0.64) at the nozzle exit. For the first problem, I use "Ubar = 0.3458" so it gives me 0.64.

2- When I use water characteristics at T=25(nu = 8.917e-7) jet does not dissipates and very strongly goes to the free surface(see figure for Ubar=0.64 which gives 1.2). Then when I use "Ubar = 0.3458" which give Unozzle = 0.64 it is still very strong(see second Figure). why my results are totally different from experiment?

3- There is only one possibility which is not adding the fluctuations at the nozzle exit which makes the jet very strong and coherent. My question is that how can I add fluctuations when I use fvoption to generate jet?

Thanks,
Farzad