Examination of the influence of empiric parameters on the aero-acoustic results of the free wake code first

Abstract

Due to society’s increased noise sensitivity and enhanced certification requirements for new helicopters, free wake methods recently experience a revival. In combination with todays increased available computing power free wake methods allow fast and efficient aero-acoustic prediction of BVI flight situations. Within the recent years at IAG the free wake method FIRST has been developed, which can be weakly coupled to flight mechanic tools such as CAMRAD II and (G)HOST. By means of a BVI forward descent flight state, a parameter study is conducted examining the influences of the spatial and temporal discretization, and of the vortex core size on the aerodynamic and aero-acoustic solution. The underlying systematics are identified and an efficient parameter strategy for future simulation setups is proposed.