engleski

Recent Advances in Pressure-Velocity Coupled Solver

Recent advances in implicitly coupled pressure- velocity algorithm are presented. A second- order collocated finite volume method on arbitrary polihedral cells is used to discretise the governing equations: the momentum and pressure equations. The pressure equation is derived by recognising the Schur- complement of the governing system. The pressure and momentum equations are inserted into a block matrix, having each coefficient as a four by four tensor. Boundary conditions derived for the specific use in the coupled solver are presented and validated. Generalized grid interface developed for the coupled solver is presented. The interface is used to couple multiple non-conformal regions into a single contiguous domain at the matrix level. Flow through a centrifugal pump, a typical case where GGI is needed for the interface between the rotor and stator is calculated using the coupled solver. A novel possibility of consistent Picard linearisation of convection term is shown, which leads to faster convergence of the coupled solver. Considering the properties of the matrix, mainly the diagonal dominance, performance of algebraic multigrid solver is examined and advances in additive correction multigrid cycle are presented as well. The performance of the solver is shown for various test cases with incompressible external and internal flows.

Hydraulic Turbomachinery, Block Coupled Solver, Pressure-Velocity Coupling, foam-extend

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