# Beginner level doubts with turbulent flow simulation setup

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 October 17, 2012, 08:26 Beginner level doubts with turbulent flow simulation setup #1 Member   Sagun Tripathi Join Date: Aug 2012 Location: Amherst, USA Posts: 78 Rep Power: 13 Hello everyone, I am attempting to simulate multiphase turbulent flow for the first time in OpenFOAM. The two fluids present in my domain are air and water (at standard conditions) with velocity of each at inlet being 5 m/s. The domain is essentially a 2-D box of dimensions 20mx0.1mx5m (empty along 'y') with water upto a height of 2m. I have the following questions in mind as I try to simulate this situation: 1. Well, this may sound really stupid but I was thinking that since there are two fluids in the domain and flow is turbulent in each, for which fluid should parameters like k, epsilon and nu_t be calculated and assigned to the patches in the 0 folder? 2. Coming to the question of calculating these parameters, could you please tell me how to go about it? I think I calculate k and epsilon using the damBreak tutorial as a reference and nu_t using the formula give on this page: http://www.cfd-online.com/Wiki/Standard_k-epsilon_model But I'm not sure if my approach is correct. Any comments? Also, I observed that for wall patches, epsilonWallFunction and kqRWallFunction are used for epsilon and k respectively with a uniform value of 0.1. How does one arrive at this value of 0.1? 3. Also, what should be the boundary condition at the inlet for a property like k or epsilon or nu_t? Because I'm defining each one of them only for one fluid and there are two fluids present in the domain at the inlet. Sorry for barging you all with so many questions. I could really use some help here. Thanks, Sagun

 October 22, 2012, 09:56 #2 Member   Sagun Tripathi Join Date: Aug 2012 Location: Amherst, USA Posts: 78 Rep Power: 13 No advice? Am I being too vague too?