CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   FLUENT (https://www.cfd-online.com/Forums/fluent/)
-   -   Poiseuille flow problem (https://www.cfd-online.com/Forums/fluent/30624-poiseuille-flow-problem.html)

 Rosie December 5, 2002 19:44

Poiseuille flow problem

Warning: this probably sounds like a dumb question

I have tried to reproduce the classic problem of flow through a tube in fluent. It works with pressure boundary conditions, but I want to prescribe a velocity boundary condition instead (and solve for the pressure gradient needed to produce laminar flow). How do I get the theoretical solution using this boundary condition? When I run the solution this way, the velocity profile never reaches a truly parabolic shape - it looks like plug or turbulent flow. I have already accounted for the transition to fully developed flow - the fully developed solution is not parabolic.

The reason I want to know how to do this is that I have some problems for branched tubes I want to solve using a velocity boundary condition. I am trying to reassure myself that I understand the physics of the way Fluent is solving the problem of straight tube flow before I solve a problem that has no analytical solution. Thanks.

 lagha December 6, 2002 17:52

Re: Poiseuille flow problem

Dear Rosy, it's a good idea to start using fluent with some basic flow. When I started with fluent three years ago, I have tried to solve the same problem as you. And I think that the mistakes was the reynolds number; I had a turbulent flow with a number of reynolds over 5000. I think that this is your problem... (for the pressure don't change any thing, just put your right velocity in the inlet and no thing in the outlet...) goog luck lagha

 All times are GMT -4. The time now is 12:27.