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-   -   simple pipe, question about BC? (https://www.cfd-online.com/Forums/cfx/65181-simple-pipe-question-about-bc.html)

Marteusz June 7, 2009 14:09

simple pipe, question about BC?
 
Hi,
I want to determine pressure drop along 2m pile, internal diameter 0.1m,
What boundary conditions (inlet, outlet) should I apply to determine correct pressure distribution. What turbulence model should be applied.

Thanks for answers

Mateusz

ckleanth June 7, 2009 21:45

I presume this relevant to the valve problem you mentioned in one of your earlier posts.

before you even start cfx, do some hand calculations of what flow to expect velocity, pressure drop etc.

Go through all of the tutorials and have the manual as reference. CFX's manual has a lot of information and is an excellent starting point for any modeling study. There is no other easy way for learning cfd; if you dont learn the basics now you will struggle later.

what conditions you apply to the inlet boundary and what physics you chose for your problem depends purely on what and the flow you intend to model. the choice of boundary conditions must also reflect any experimental data you will have, so do your homework. In the CFX manual read: ANSYS CFX-Solver Modeling Guide > Boundary Condition Modeling > Using Boundary Conditions

there is no right or wrong turbulence model, they all have been specifically developed to account for the effects of turbulence in the flow without using a prohibitively fine mesh and/or direct numerical simulation. if you will compare the results to papers etc k-e is very well known and robust model yet again it has its limitations in which you can further read in the CFX manual: ANSYS CFX-Solver Modeling Guide > Boundary Condition Modeling > Turbulence Models


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