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-   -   How many prism layers should be added in a pump simulation? (http://www.cfd-online.com/Forums/cfx/65491-how-many-prism-layers-should-added-pump-simulation.html)

Jasmine June 16, 2009 15:27

How many prism layers should be added in a pump simulation?
 
How much influence will the number of cells inside Boudary layers influence the final flow field inside a centrifugal pump. usually how many layers should be used? Is 5 enough?

ghorrocks June 16, 2009 18:34

Hi,

This is problem dependant. Some designs will require more, some will require less. Also it will depend on the level of accuracy you want in the simulation - is an error of 30% acceptable? Then don't bother about inflation layers at all. Do you need 5% error - then you will need accurate boundary layer modelling.

You will have to figure it out for your design and for the level of accuracy you want. The documentation has some good guides as to general principles but you have to adapt it to your circumstance.

Glenn Horrocks

paulo June 17, 2009 16:02

Hi,

Just to be more precise, under my experience. :)

You have to run your problem until convergence, and evaluate the y+ over the wing.

It must be at least less than 100, if your problem is incompressible.

If it is more than 100, you will have to put more layers in a way that the domain gets more refined.

Best Regards,

Paulo Rocha.

paulo June 17, 2009 16:05

Adendum :)

It is better to use hex meshes at least in the boundary layer region. Avoid tetrahedrons there.

Best Regards,

Paulo Rocha


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