Development and Validation of a Massively Parallel Flow Solver for Turbomachinery Flows

This paper presents the development and validation of the unsteady, three-dimensional, multiblock, parallel turbomachinery flow solver, TFLO. The Unsteady Reynolds Averaged Navier-Stokes (Unsteady RANS) equations are solved using a cell-centered discretization on arbitrary multiblock meshes. The solution procedure is based on efficient explicit Runge-Kutta methods with several convergence acceleration techniques such as multigrid, residual averaging, and local time-stepping. The algebraic Baldwin-Lomax, the one-equation Spalart-Allmaras, and the two-equation Wilcox k-w turbulence models are implemented. The solver is parallelized using domain decomposition, an SPMD (Single Program Multiple Data) strategy, and the Message Passing Interface (MPI) Standard. A mixing model and a sliding mesh interface approach have been implemented to exchange flow information between blade rows in both steady and unsteady rotor/stator interaction flows. The dual-time stepping technique is applied to advance unsteady computations in time. This paper focuses heavily on the initial validation of the flow solver, TFLO, with emphasis on steady-state calculation of multiple blade-row flows. For validation and verification purposes, results from TFLO are compared with both existing experimental data and computational results from other software used in industry. The large set of cases tested increases our confidence in the ability of TFLO