Comprehensive optimization of aerodynamic noise and radar stealth for helicopter rotor based on Pareto solution

Abstract

To reduce the aerodynamic noise and radar cross section (RCS) of the helicopter rotor without sacrificing its aerodynamic characteristic, a comprehensive optimization method (COM) based on Pareto solutions is presented. An initial model of the rotor is created by full factorial design (FFD) and meshed by unstructured grid techniques to participate in the calculation and analysis of flow field and electromagnetic scattering field. The aerodynamic characteristics of the rotor flow field are simulated by computational fluid dynamics (CFD) method based on Navier–Stokes (N–S) equations and k–ε standard viscous model. According to the aerodynamic performance constraints of not reducing rotor lift, the thickness noise and the loading noise solved by Farassat 1A formula and the RCS value calculated by physical optics (PO) method and physical theory of diffraction (PTD) are designed as the comprehensive optimization goals. With the progress of the comprehensive balance analysis of these stealth indicators for the rotor models to be optimized, an excellent model with high comprehensive stealth performance and aerodynamic characteristic is generated by the proposed optimization method based on Pareto solutions. In addition, the effects of the models and parameters of each part of the rotor on these characteristics including aerodynamic lift, RCS, thickness noise and loading noise are analyzed in detail. It is effective and impactful of the comprehensive optimization method to deal with the multidisciplinary optimization problems of aerodynamic noise and radar stealth for helicopter rotor.