I work on the discretisation of ***unsteady convection-diffusion equations*** and with "compressible fluid"

I have some questions:

1- do I must applie requirements for boundedness (Scourbourough + Positivity ) to continuity equation in unsteady equations in order to obtain CFL conditions.

2- do some one have references a bout how to do discretisation of ***unsteady convection-diffusion equations*** with finite volume method and if the density is variable "compressible fluid".

I work in a case of free surface and the density and the viscosity are a mixture between water and gaz.(fluid 1 +fluid 2)

I work on the discretisation of PHOENICS code equations, so do some one can show me where I can find documents a bout the discretisation of PHOENICS code equations and there conditions of stability (CFL).

(1). You should send e-mail directly to CHAM, the vendor of the code, it is one of the sponsor of this forum. (2). You should also visit their website. The list of the sponsor can be found here on the bottom of the cfd-online page.

You can take a look in the technical report TR99s (PHOENICS Equations) regarding the discretisation question - visit the cfdShop on CHAM's homepage and look for PHOENICS Shareware documentation. Please do contact CHAM's Support team (support@cham.co.uk) with regard to your other queries.