# Flux vector splitting of Inflow/outflow BC

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

 March 24, 2002, 21:30 Flux vector splitting of Inflow/outflow BC #1 Quain Tchew Guest   Posts: n/a Hi I'm reading a code. In the code, inflow/outflow bc is handled with Flux vector splitting: normal flux on the boundary face of the cell = integrate_on_the_face ( ((A+)*(Win)+(A-)*(Wex))*n ) A+ is the positive Jacobian Matrix A- is the negative Jacobian Matrix Win is the primal var on the inner side of the face Wex is the primal var on the outer side of the face What does that mean? Where can I fined a detail introduction about Flux vector splitting of Inflow/outflow BC on web?

 March 25, 2002, 09:43 Re: Flux vector splitting of Inflow/outflow BC #2 gita Guest   Posts: n/a Hi, You can refer to this book: C. Hirsch, Numerical Computation of Internal and External Flows, Vol. 1 and 2, 1988 Wiley. There are different types of flux vector splitting schemes like van Leer(based on Mach No),Stegar-Warming(eigenvalue based),hybrid FVS(flux vector splitting) like AUSM(Advection Upstream Splitting Method-pressure based splitting). If you're new to these schemes(flux-difference and flux-vector),then I suggest you should read Hirsh so that you gain some insight into those numerical methods. Basically these compressible schemes split the fluxes into positive and negative fluxes(inviscid) across each cell of the volume so that the correct flow information is incorporated(direction of the propagation of wave speeds). When you deal with compressible NS flows,you apply these flux-difference/flux-vector/hybrid splitting schemes only for the inviscid part. Do you want to know the physical meaning behind these different splittings? I can explain... Regards

 March 25, 2002, 09:54 Re: Flux vector splitting of Inflow/outflow BC #3 Quain Tchew Guest   Posts: n/a Hi! gita, Thank you. I have read some books about that. But I still don't know how to apply flux vector splitting in inflow and out flow boundary. I met this problem when I was reading the NSC2KE code(http://pauillac.inria.fr/cdrom/prog/unix/nsc2ke/eng.htm). In the page 10 of the guide of NSC2KE, there is a paragraph about "Inflow and outflow weak boundary". But I can not understand. Regards Quain Tchew

 March 25, 2002, 11:25 Re: Flux vector splitting of Inflow/outflow BC #4 Praveen Chandrashekar Guest   Posts: n/a Refer to the paper by Steger and Warming as suggested in the manual.

 March 25, 2002, 19:43 Re: Flux vector splitting of Inflow/outflow BC #5 Quain Tchew Guest   Posts: n/a oh, I can't find it. But I think I have catched on it.