# SIMPLE help

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

 July 24, 2008, 07:42 SIMPLE help #1 Fernando Herrera Guest   Posts: n/a Hi, I need from someone that has applied the algorithm and understands it very well. In this moment Im starting very small, at: http://www.students.ncl.ac.uk/f.j.he...owexample.html There is a small diagram of my actual process. It is the flow of a gas through a pipe. The black arrows are known velocities and the blue cells represent known pressures (in this case both are zero). My solution procedure is this one: 1) First I assume a pressure distribution on the black cells as well as a velocity flow 2) Solve the momentum equations for the red arrows (horizontal and vertial) Six for the horizontal and 3 for the vertical velocities 3) With the new velocities calculate the pressure correction. And here is where the problems start. I don't know why, but when I solve the system of equations for the pressure corrections the results are unrealistic (negative pressures) What would you do for the solution of this small system? What boundary conditions you would use? Is the system too small and therefore not well defined?

 August 10, 2008, 03:54 Re: SIMPLE help #2 Anishtain4 Guest   Posts: n/a a system is not well defied for small sized just results are unrealistic. a negative pressure is not wrong, the equation give you the relative pressure field that you should correct it later. if you are using the staggered grid you should have 4 equation for the vertical solution. inflow is clear and just put a very low viscousity for the outflow cells as patankar mentiond it. it won't affect your solution. finally take a look ant 'patankar' or 'malalaskar' books they'll be good guid for you.

 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 zouchu Main CFD Forum 1 January 20, 2014 18:02 renyun0511 OpenFOAM Programming & Development 0 November 4, 2010 02:38 fakor Main CFD Forum 1 August 30, 2010 11:21 Fabio Main CFD Forum 4 April 9, 2006 11:35 benedikt flurl Main CFD Forum 2 April 14, 2005 06:54

All times are GMT -4. The time now is 10:33.

 Contact Us - CFD Online - Top