Numerical schemes in PHOENICS code
The Non linear convection and Crank Nickolson schemes, implemented in the PHOENICS code, are activated by source term associated to a transport variable other than the velocity components.
How the discretized momentum equations are modified by this activation procedure ? Thank you. Hydraulic and Environemental Modeling Laboratory National Engineering School of Tunisia 
Re: Numerical schemes in PHOENICS code
The higherorder numerical schemes embodied in PHOENICS are fully described in: http://www.simuserve.com/cfdshop/vol122.htm#malin
The document includes a description of the finitevolume analogues of the convection terms along with their implementation in the PHOENICS GX routines. Mike Malin 
Re: Numerical schemes in PHOENICS code
is phoenics a coupled or uncoupled solver?

Re: Numerical schemes in PHOENICS code
I am not sure what you precisely mean, but I presume that you are referring to the velocitypressure coupling in the numerical solution procedure. The default in PHOENICS is to use uncoupling, but for singlephase flows an option is now available to carry out the solution with a coupled solver.

Re: Numerical schemes in PHOENICS code
What I mean is it a pressure based ie uncoupled (SIMPLE PISO etc) or is it a time iterative scheme ie coupled (Cranknicholson, rungekutta etc). also what spatial differencing methods are employed

Re: Numerical schemes in PHOENICS code
The default is to use uncoupled velocitypressure coupling, i.e. to use segregated continuity and momentum equations and to solve in an iterative manner by means of the SIMPLEST algorithm, which is a variant of the pioneering SIMPLE method of Patankar and Spalding. Timemarching to a steadystate by use of SIMPLEST is permitted as an alternative to repeated sweeps of the solution domain.
For singlephase flows, an option exists to solve the continuity and momentum equations simultaneously by means of an algebraic nultigrid solver. Specifically, PHOENICS 2.2 and later releases provide for 5 alternative linear schemes, and 12 alternative nonlinear schemes. The linear schemes are based on the Kappa formulation, and comprise CDS, QUICK, the cubic upwind scheme (CUS), the linear upwind scheme (LUS) and Fromm's scheme. The nonlinear schemes extend the Kappa formulation so as to employ a flux limiter to secure boundedness at the expense of reduced accuracy. The nonlinear schemes currently available are: SMART, HQUICK, UMIST, Koren, Superbee, Minmod, OSPRE, van Albada, MUSCL, CHARM, HCUS and vanLeer harmonic. All these schemes are documented in the reference cited in my message of 31/07/00. 
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