CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

Shock Tube

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   June 7, 2005, 04:03
Default Shock Tube
  #1
Pooria Sattari
Guest
 
Posts: n/a
Dear Friends,

I have written a code for 1D-Shock Tube Problem (using Lax Method),butI get wrong results.

Has anybody written a code in C for this problem using Lax Method?

If yes,Could you send that for me?

Thanks, Sincerely, Pooria Sattari
  Reply With Quote

Old   June 7, 2005, 10:30
Default Re: Shock Tube
  #2
Nick
Guest
 
Posts: n/a
What is wrong with your results? Isn't the Lax method 1st order? What are your boundary conditions? Have you discretized conservatively? Just some things to think about...

Nick
  Reply With Quote

Old   June 7, 2005, 12:31
Default Re: Shock Tube
  #3
Pooria Sattari
Guest
 
Posts: n/a
Thanks for your response,

Initial Conditios are: P1=1 rau1=1 P2=0.1 rau2=0.1 gamma=1.4

My Problems are :

after t=0.01 my results get diverged and I have unphysical results for u(velocity) and pressure.This happens with deltat greater than 0.0001.

Other Problem is that I can not set deltat less than 1e-7,because of memory shortage.

It would be very nice to hear from you.

Sincerely, Pooria.
  Reply With Quote

Old   June 7, 2005, 12:52
Default Re: Shock Tube
  #4
Nick
Guest
 
Posts: n/a
Are you sure that those initial conditions are appropriate? I mean, have you checked all these values from the compressible flow tables?

As far as your DT is concerned: How many nodes do you have and what is your stability criteria? Most of the time non-physical results come from a non-stable situation.
  Reply With Quote

Old   June 8, 2005, 02:52
Default Re: Shock Tube
  #5
upwind
Guest
 
Posts: n/a
You should be able to set any value of deltat : it appears you are storing values of dependent variables at all time levels. You need to store values of dependent variables only for two time levels and keep swapping values at the end of each time step.
  Reply With Quote

Old   June 14, 2005, 00:55
Default Re: Shock Tube
  #6
Ritesh
Guest
 
Posts: n/a
Apart from the initial condition, you just use reflecting boundary conditions, you can look into a book by R. J. Levaque (chapter 7) for boundary conditions. let me know, for any further details
  Reply With Quote

Reply

Thread Tools
Display Modes

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 Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shock tube simulation harish FLUENT 5 January 25, 2014 03:20
HLL Riemann Shock Tube Matlab Problem Luke F Main CFD Forum 1 July 7, 2009 13:44
shock tube validation AB Main CFD Forum 3 December 10, 2004 08:31
shock tube validation AB CD-adapco 0 November 21, 2004 19:43
Shock tube problem AB CD-adapco 1 November 9, 2004 01:25


All times are GMT -4. The time now is 06:59.