# How to model this case in fluent?

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 July 13, 2007, 17:34 How to model this case in fluent? #1 hjzy Guest   Posts: n/a Hi, fluent fans: I have a problem in solve this case: the tube has solid walls all around - same boundary conditions on all four sides - left side, right side, top side, and bottom side. There is a high pressure region on the left and a low pressure region on the right separated by a diaphram. At t=0, the diaphram is removed and the pressure will create a flow from left to right. Which kind of model can I use to simulate this condition. I can try it as a 1d or 2d problem. Thanks!

 July 16, 2007, 17:53 Re: How to model this case in fluent? #2 hjzy Guest   Posts: n/a this is a shock tube problem. I have tried many method, but still can not the result, did any one can help? Thanks in advance!

 July 17, 2007, 14:20 Re: How to model this case in fluent? #3 sujith Guest   Posts: n/a This problem should possible using unsteady density based solver. you have to patch the initial values of pressure. I havn't tried this myself. If you have already tried this and had any difficulties, please share it with us

 July 17, 2007, 19:11 Re: How to model this case in fluent? #4 yzheng Guest   Posts: n/a I have tried this problem, but still can not get accurate result. I just make a rectangular, 8.2m Ã- 2m, four sides all defined as walls, and make a line just between the center(x=0) as an interior, then make two zones, left has high pressure at about 3.5atm and density=0.445, the right side has the lower pressure at about 0.5atm and density=0.5. I just use patch after the initialize. In fluent, read the case, then check the grid, it's ok. Define-> models->solver->coupled->unsteady Define->energy Define->viscous ->k-epsilon(2-eqn) Define->material ->ideal gases Define->operation condition ->operation pressure=0 Define->boundary condition(nothing need to define) Solve->controls->solution controls->pressure velocity coupling->piso Solve->monitors->convergence criterion(change all values to 0.000001) Solve->initialization->gauge pressure=3.5atm, temperature=400k Solve-> initialization->patch initialization->set the pressure for the left zone3.5atm, temperature=2789k, set the pressure for the right zone0.5atm, temperature=400k, set all the velocity=0 Solve->iterate, set the time step size=0.0001s, then iterate. But it can not convergence, after about 500 steps, it is said, divided by zero. The problem is the pressure of the left side changed a lot, especially at the x=-4.1m, but the center is changed not so much, and the pressure in the right zone changed a little near the center. This is not as expected, I don't know why? Any advices? Thanks in advance.

 July 17, 2007, 19:13 Re: How to model this case in fluent? #5 yzheng Guest   Posts: n/a I only have the version of 6.2, so it don't have density based solver.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Tim CFX 1 October 7, 2009 06:19 bzhang7 FLUENT 0 May 27, 2009 13:36 Jiedong FLUENT 0 January 22, 2009 03:57 D. L. FLUENT 3 July 31, 2008 07:40 Lam CD-adapco 6 June 24, 2003 20:21

All times are GMT -4. The time now is 09:49.

 Contact Us - CFD Online - Top