UDF for turbulence models
Hello all,
Can a completely new turbulence model be implemented with a UDF? Specifically I'm interested in the zeta-f, v2-f, and RSA models. My understanding so far is that it is possible to do the zeta-f and v2-f models because they also use the original k-epsilon transport equations. However, in the RSA model, k and epsilon have algebraic relations and are not defined by transport equations. Since this is a different implementation of k and epsilon I'm unsure if the use of a UDF is possible for the RSA model. Any insight is appreciated, Tim |
You may could model it by entering sources, changing variables in turbulent models panel. Or, write two user defined scalars for turbulent parameters.
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I am new to using UDF but I wanted to build a zero equation turbulence model and use it in FLUENT. Can you help me with this? |
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I am struggling with implementing a new intermittency transport equation that I have derived in fluent and you seem to be a very knowledgable person in this regard. I understand that I have to use UDS. But I am not sure how I should change the value of intermittency inside the UDF? I am guessing that I have to use DEFINE_ADJUST for that reason but then again I do not know how to access (read) the value of intermittency from the solver. Also two other problems: 1) For adding source terms to intermittency can I simply add it through the sources tab in the fluids window or it has to be done through UDF as well. 2) Diffusion term: This is the part that I literally do not have any clue about. Any help is much appreciated. Sorry if my problems sound childish to you. I have been using CFX for quite a while and I know how to work with that but I am quite a newbe in fluent. I would really really appreciate it if you can help me with that. I am lost and do not have much time. Thanks a lot, Ali |
energy residual convergence problem
hello frnds..
give the suggestion to e for my problem.. my analysys is double pipe heat exchanger with two different turbulator inserts. and i used counterflow arrangement turbulent k-epsilon(2 eq) stand wall fun. hot inlet-413 k,1.3 kg/s cold inlet-298k,1.3 kg/s solution scheme-pressure-velocity based simple, second order my problem is..during my solution in fluent cfd energy residual is not converged and its value increases and reach to 1e+08.. plz gys give me the suggestion.. thanks in advance |
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My guess is your mesh or your BC is wrong. |
energy residual convergence problem
my boundary condition is:
hot inlet-413k,1.3 kg/s hot outlet-pressure based cold inlet-298k,1.3 kg/s cold outlet-pressure based all wall boundarries except outer pipe are copper material. and outer pipe is of aluminium. inserts wall are also of copper. mesh quality: min orthogonal quality-1.23155e-01 maxi. aspect ratio- 3.34364e+01 and again i dont get convergence in energy residual it increasing and goes toward... e+8. can any one help me.. thanks in advance frnds. |
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