# Inviscid flow calculator, Entropy rise?!!

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

 LinkBack Thread Tools Display Modes
 April 8, 2003, 11:21 Inviscid flow calculator, Entropy rise?!! #1 MJK Guest   Posts: n/a Hello there, I was wondering how is possible that inviscid flow calculators (Euler Solvers) can predict entropy rise correctly? Noting that viscoity and thermal conductivity are the only means which could produce loss and they are taken to be zero in inviscid flow, then how is it possible to have irreversibilities due to shocks when inviscid model is used? Thanks MJK

 April 8, 2003, 11:42 Re: Inviscid flow calculator, Entropy rise?!! #2 Pao Guest   Posts: n/a you have artificial viscosity in Euler code. Have you noticed total pressure loss at lot at low Mach in Euler code when there is reverse flow?

 April 8, 2003, 11:51 Re: Inviscid flow calculator, Entropy rise?!! #3 MJK Guest   Posts: n/a Thanks Pao, Right. For central schemes like Jameson's you set artifitial viscosity to a value giving you right answer. But smarter scheme like upwind usually need no setting for artifitial diffusion and they still give a correct answer! So how smart should be these schemes with no tuning, they automatically feed in a right amount of artifitial diffusion to predict entropy rise correctly. Thanks again MJK

 April 9, 2003, 03:36 Re: Inviscid flow calculator, Entropy rise?!! #4 Kevin Guest   Posts: n/a The dissipation in the inviscid schemes is needed for stability purpose. The entropy rise (jump) accros a shock is generated by the discontinuity of the computed value : Euler equations fulfil the Rankine-Hugoniot jump relations and so give an entropy rise. I don't know if it's right or complete but maybe it will help you. Regards, Kevin

 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 Dave CFX 4 March 6, 2008 11:33 S.T Main CFD Forum 6 December 10, 2007 09:07 Ferdinando FLUENT 2 October 30, 2007 18:26 jane luo Main CFD Forum 15 April 12, 2004 17:49 Atit Koonsrisuk CFX 12 January 2, 2003 13:40

All times are GMT -4. The time now is 17:17.

 Contact Us - CFD Online - Top