Numerical Simulation of Rotor in Hover and Forward Flight

Qinghe Zhao,Dan Zhang

doi:10.1051/matecconf/201817903011

Abstract

The flow around rotor is numerical simulated in hover and forward flight based on multi-structured grid. In hover the flow field can be transformed into a steady-state flow field in the rotating coordinate system. The experimental data of Caradonna and Tung rotor is used to verify the numerical simulation result. The numerical results compare well with the experimental data for both non-lifting and lifting cases. Non-lifting forward flight is simulated and the prediction capabilities have been validated through the ONERA two-blade rotor. The pressure distributions of different positions under different azimuth angles are compared, which is in good agreement with the experimental data. There is unsteady shock wave when forward flight. Dual-time method is used to obtain unsteady flow field with rigid moving grid in the inertial system.

Highlights

The flow around rotor blade has many different characteristics from the fixed wing
The azimuthal step used for forward flight is 0.25o, which is equivalent to a rotational period includes 1440 time steps, 50 inner iterations is used in each time step
A numerical approach is presented for the simulation of hovering and forward flight flow field based on multi-block grid

Summary

INTRODUCTION

The flow around rotor blade has many different characteristics from the fixed wing. The local velocity of rotor varies linearly with the radius of rotation. The coordinate system is established on the blade and rotates together with the rotor. In the rotational coordinate system to solve the equation can greatly improve the hover flow field calculation efficiency. The forward flight involves asymmetric flow fields and cannot be solved in a rotating coordinate system. It should be simulated unsteady flow field, which require more computational resource. Simulation progress in Europe is introduced [11] Despite these methods, multi-block structured grids are still the most commonly used form and are widely used in solving rotor flow field.

Methodologies for hover case

Methodologies for unsteady flows

Mesh movement

THE HOVER CASE

FORWARD FLIGHT CASE

CONCLUSION