[ndabir]

Hi all,


Does anybody have any experience with simulating water as an compressible liquid in fluent? I have already written an udf file for relation between density and pressure. But since I want to use the explicit solver (because Fluent help says that this solver is better for capturing shock), when I use it I get this error:

"global time stepping cannot be used for incompressible flow"

however I have changed the material to water and the density and speed of sound to udf. I think this should be enough for fluent to realize that I am solving compressible flow.

Anybody has any idea how to get rid of this error?

[LuckyTran]

Originally Posted by ndabir

Hi all,


Does anybody have any experience with simulating water as an compressible liquid in fluent? I have already written an udf file for relation between density and pressure. But since I want to use the explicit solver (because Fluent help says that this solver is better for capturing shock), when I use it I get this error:

"global time stepping cannot be used for incompressible flow"

however I have changed the material to water and the density and speed of sound to udf. I think this should be enough for fluent to realize that I am solving compressible flow.

Anybody has any idea how to get rid of this error?

You can't use global time stepping for incompressible flows (pressure-based solver) or density-based implicit time stepping.

Make sure you are using the explicit density based solver (regardless of how you use UDFs to take care of everything else).

[ndabir]

Thanks for your reply. I use explicit solver (density-based) with a udf for water density. But still have the same error. it seems fluent cannot realize the udf. I guess the only EOS fluent supports with explicit solver is "Ideal gas".

has anybody simulated water as compressible with explicit solver?