Assessment Of A Hybrid Eulerian-Lagrangian Method By Comparison With Its Parent Codes

Abstract

A hybrid Eulerian-Lagrangian numerical method is developed to simulate the blade-vortex interference of rotorcraf ts. The RANS solver ROSITA is used to solve the near-body region covered by Eulerian grids, while a Lagrangian solver developed from DUST is employed for the grid-free farfield to preserve the wake vorticity. The coupling algorithm between the two solvers is such that the sectional aerodynamic loads of lifting bodies integrated from RANS solution are transformed into bound vortex strength of lifting line elements based on Kutta-Joukowski theorem and the induced velocity from all the Lagrangian elements corrects the grid interface boundary in return. The hybrid solver is assessed by three well-documented benchmark cases. The achieved results show good agreement with the experimental data and correlated well with the parent codes' results, demonstrating the capability of vortex preservation and the efficiency of the proposed solver.