로터 정지비행 점성유동 해석을 위한 비정렬 격자 기법

Abstract

A three-dimensional viscous flow solver is developed for the prediction of aerodynamic behavior of hovering helicopter rotor blades using an unstructured mesh methodology. The flow solver utilizes a cell-centered finite-volume scheme that is based on the Roe`s flux-difference splitting and an implicit Jacobi/Gauss-Seidel time integration. The effect of turbulence is estimated by the Spalart-Allmaras one-equation model coupled with a wall function boundary condition. A solution-adaptive mesh refinement technique is adopted to capture the tip vortex. Calculations are performed for non-lifting and lifting rotor cases. Comparison of the inviscid and viscous results indicates that inclusion of viscosity significantly affects the surface pressures and the blade airloads for a lifting rotor at transonic tip speed. Good agreements are obtained between the numerical result and the experiment for both the blade loading and the tip vortex behavior.