An Efficient Helicopter Main Rotor Trim Method based on Computational Fluid Dynamics

Abstract

This paper introduces a multi-dimensional “delta trim method” for computational fluid dynamics (CFD) simu-lations to compute the blade control settings that are essential for predicting rotor aerodynamics. The pre-sent trim method is based on the standard “delta trim method”, but it achieves higher computational efficien-cy by using a combination of multi-level grid spatial and temporal resolutions. Two representative benchmark results are presented, including the AH-1/OLS rotor in forward flight and the HART-II rotor in descent flight. The numerical activities demonstrated the effectiveness of the new trim method. In addition, the novel meth-od saves approximately 12% and 31% CPU time in the AH-1/OLS rotor and HART-II rotor cases, respective-ly, compared to the standard “delta trim method”.