|August 28, 2013, 01:45||
Calculation of initial k for RAS turbulence models
Join Date: Jan 2013
Posts: 98Rep Power: 4
Dear Foam users,
I want to ask about the initial calculation of k (turbulence kinetic energy). I am studying cavitating flow inside of the nozzle with different turbulence models ( kepsilon, RNGkepsilon, kwSST).
According to users guide k is calculated with this formula: k=3/2(u)^2
u corresponds to fluctuating velocity which equals to 5% of inlet velocity. Just i am confused about this point. As you can see in the attached figure i have one domain inlet (Vin=3.1 m/s) and one nozzle inlet (Vin=12.8m/s). AS you know that cavitation and turbulence take place close the nozzle inlet.
I tried both inlet velocity for calculation initial value of k and final result of calculation not change too much, but i want to know that which inlet velocity value should be used for initial calculation of k for the nozzle flows.
thanks in advance.
|August 28, 2013, 03:52||
Join Date: Oct 2012
Posts: 2,186Rep Power: 16
i think you better set the values of main entrance for velocity and length(for omega or epsilon formulas)
Because only at boundaries you should use a model,the rest of geometry should be solved by the solver itself.
Correct me if anyone has another opinion.
Injustice Anywhere is a Threat for Justice Everywhere.Martin Luther King.
To Be or Not To Be,Thats the Question!
The Only Stupid Question Is the One that Goes Unasked.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Moving mesh||Niklas Wikstrom (Wikstrom)||OpenFOAM Running, Solving & CFD||122||June 15, 2014 06:20|
|AMI interDyMFoam for mixer nu problem||danny123||OpenFOAM Programming & Development||8||September 6, 2013 02:34|
|alphaEqn.H in twoPhaseEulerFoam||cheng1988sjtu||OpenFOAM Bugs||14||September 18, 2011 13:46|
|lift and drag on ship superstructures||vaina74||OpenFOAM Running, Solving & CFD||3||June 8, 2010 12:30|
|Problems with simulating TurbFOAM||barath.ezhilan||OpenFOAM||13||July 16, 2009 05:55|