# Solutions of Nozzle Flows by MacCormack Technique

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

 September 21, 2003, 06:10 Solutions of Nozzle Flows by MacCormack Technique #1 worasit Guest   Posts: n/a From the cfd book of John Anderson, Jr, I have tried to follow the solution technique for converging-diverging nozzle flows by using of MacCormack technique. But I found the problem about the purely subsonic case. This book did not show the solution of this case by using the governing equations in conservation form. So I have developed my code base on the governing equation in conservation form and it gave the correct !! solution for the case with normal shock (but the numerical solutions had some discrepancy). When I perform the purely subsonic case, the numerical solutions was wrong--differ from the solution in the foregoing section of that book. My questions are 1. Can the governing equation in conservation form be used with subsonic flows? 2. If the answer of the first question is no, does it mean that the conservation equations are appropriate for case with shock only and the non-conservation equations are appropriate for the case without shock. 3. If the answer of the first question is yes, what is the possible error in my code? 4. Where can I find the excellent and clear explanation about using and caution of these two formulations of governing equations of fluid flow?

 September 21, 2003, 06:35 Re: Solutions of Nozzle Flows by MacCormack Techni #2 Jonas Larsson Guest   Posts: n/a The governing equations (Euler equations I assume) are valid both for subsonic and transonic flows. The MacCormack scheme isn't very good at cases with low Ma numbers though. If your Ma number goes below say 0.3 you will probably get stability/convergence problems with that scheme.

 September 21, 2003, 11:00 Re: Solutions of Nozzle Flows by MacCormack Techni #3 Abhijit Guest   Posts: n/a Hi, I programmed the scheme for CD nozzle. my inlet was supersonic and outlet was subsonic. The shock was best resolved by Roe's scheme. For low mach no. roe's scheme blows up bcos the jacobian of flux vector become near to singular....however mac-cormack works if more dissipation is added. Conservative form is the mother of all forms. It will work in any situation....compressible/incompressible,you must obiviously use correct the scheme. For compressible flows conservative form is recommended.However I have seen papers where people use finite difference for compressible flows( with some correction terms). Follow this link if you need to know more about conservative/non-conservative forms. http://personalpages.umist.ac.uk/sta...hydr/INDEX.HTM Also try other CFD books by Hirsch(this one is good), D.A. Anderon, Pletcher. Hope this helps. abhijit

 September 21, 2003, 18:34 Re: Solutions of Nozzle Flows by MacCormack Techni #4 Maciej Matyka Guest   Posts: n/a Hi, Maybe you will be interested to see my solution for technique presented in John Andersson book: see: "Prandtl-Meyer expansion wave solution" PDF file on my web page: http://panoramix.ift.uni.wroc.pl/~maq Maciek

 September 29, 2003, 11:27 Re: Solutions of Nozzle Flows by MacCormack Techni #5 srikanth Guest   Posts: n/a please send me the solutuions. thnk you.

 September 29, 2003, 11:38 Re: Solutions of Nozzle Flows by MacCormack Techni #6 srikanth Guest   Posts: n/a i am a post graduate student.i am doing a course in CFD let me know the solutions of the above problems edpecially "sub sonic-super sonic flow in CD nozzle", if possible.

 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 RcktMan77 Main CFD Forum 5 September 15, 2015 11:31 d.vamsidhar FLUENT 0 November 24, 2005 02:45 Kalyan CD-adapco 4 August 17, 2005 17:58 Valdemir G. Ferreira Main CFD Forum 0 December 7, 1999 13:25 Zhou Hua Main CFD Forum 0 May 7, 1999 00:10

All times are GMT -4. The time now is 05:04.