1,721,176 research outputs found
Turbulent Flow Calculations With a Two-Equation Turbulence Model on Unstructured Triangular Meshes
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Three-Dimensional Unstructured Grid Euler Method Applied to Turbine Blades
No full textFlow through a turbine annular cascade is calculated using a three-dimensional Euler method based on unstructured tetrahedral meshes. The governing equations are integrated in time using an explicit RungeKutta time-stepping. Inviscid flux terms are diecretized using a cell-centered finite-volume formulation with the Roes flux-difference splitting. Tetrahedral meshes around turbine blade are generated using an advancing-front technique with a forced geometric periodicity between the blades. Good agreements are obtained between the present calculation and the experiment not only for the surface pressure distribution on the blade but also for the flow behavior through the flow passage between the blades
Investigation of Transonic Fan Rotor Flows Using an Unstructured Mesh Viscous Flow Solver
No full textA three-dimensional viscous flow solver is developed for turbomachinery components using unstructured meshes. The numerical scheme is based on the Roes flux-difference splitting with an explicit Runge-Kutta time integration. A standard k-e turbulence model with a wall function boundary condition is adopted to simulate high Reynolds number viscous flows. To accelerate the convergence to steady state, local time stepping and implicit residual smoothing are applied. The code has been applied to calculate flows through a transonic axial fan rotor operating at near peak effciency and at near stall. Blade-to-blade contour plots are compared with the experimental data to validate the present solver. Calculated Mach number distributions are compared with laser anemometer data within the blade row to quantify the accuracy of the calculations. Details of the flow through the rotor including the tip clearance gap are investigated.The work was supported by the Korea Science and Engineering Foundation under Core
Research Grants 951-1006-024-
Aeroelastic Study for HART II Rotor Using Unstructured Mixed Meshes
No full textIn the present study, aeroelastic response of HART II rotor blade has been numerically investigated using a coupled CFD/CSD method. Aerodynamic forces were calculated from a Navier-Stokes CFD flow solver based on unstructured mixed meshes. In the mixed meshes methodology, body-fitted prismatic/tetrahedral mesh was used in the near-body flow region to handle complex geometries easily. Cartesian mesh was used in the off-body flow region and high-order accurate weighted essentially non-oscillatory scheme was employed to implement high-order spatial accuracy. In the FEM-based CSD solver, an elastic deformation of the rotor blade was obtained on the basis of nonlinear Euler-Bernoulli beam theory. The coupling between the CFD and CSD solver was performed in a loosely coupled manner by exchanging the aerodynamic loads and elastic deformation of the rotor blade. An overset mesh technique was adopted to simulate rotating motion of the rotor blade and to exchange flow information between two different meshes. In addition, spring analogy was used to implement elastic deformation of the rotor blade. Coupled CFD/CSD method was applied to the HART II rotor in forward flight to examine aerodynamic performance and aeroelastic effect of the rotor. Aerodynamic loads and elastic deformation of the rotor blade were calculated and compared with experimental results and other research efforts. Overall, the present results were in good agreement with the experimental data. In addition, adaptive fine mesh was used to capture tip vortex trajectory and BVI (blade-vortex interaction) phenomenon more accurately.
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