engleski

A NOVEL PRESSURE-VELOCITY COUPLING ALGORITHM

During last two decades research efforts within the field of CFD has been directed to solving physically and computationally more demanding problems, leaving the problem of pressure-velocity coupling in solving Navier-Stokes equations somewhat neglected. Finite volume methods for solving fluid flow problems are mostly based on SIMPLE-like methods. SIMPLE algorithm was originally defined on staggered grids on which it is consistent and physically clear. On collocated grids SIMPLE-like methods require non-physical pressure boundary conditions and use of arbitrary interpolations with a possible negative consequence to the solution accuracy. Their convergence rate strongly relies on method's underrelaxation factors. The theoretical research here presented has led to a new pressure-velocity coupling method - FLOP algorithm (Flux LOoping for Pressure drop) which does not suffer from such drawbacks on collocated grids, nor requires underrelaxation factors and that has a significantly higher convergence rate than SIMPLE-like methods, while keeping the segregated solving procedure. A significantly higher convergence rate and efficiency of the FLOP algorithm is noted, along with independency of No. of iterations on grid size. Due to only physical interpolations used and fulfillment of the continuity equation constraint during the iterative process, the new FLOP algorithm does not require any stabilization procedure. This is opposite to all SIMPLE-like algorithms that require underrelaxation factors for wich optimal values are problem dependent.

CFD; pressure-velocity coupling algorithm; FLOP algorithm; SIMPLE algorithm

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