Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover

Purpose: The design of main rotor blade tips is of interest to helicopter manufactures since the tip details affect the performance and acoustics of the rotor. The paper aims to discuss this issue. Design/methodology/approach: In this paper, computation fluid dynamics is used to simulate the flow around hovering helicopter blades with different tip designs. For each type of blade tip a parametric study on the shape is also conducted for comparison calculations were performed the constant rotor thrust condition. The collective pitch and the cone angles of the blades were determined by at an iterative trimming process. Findings: Analysis of the distributed blade loads shows that the tip geometry has a significant influence on aerodynamics and aeroacoustics especially for stations where blade loading is high. Originality/value: The aeroacoustic characteristics of the rotors were obtained using Ffowcs Williams-Hawkings equations

Experimental and numerical study of rotor aeroacoustics

The work documents recent experiments at the Kazan National Research Technical University named after A.N. Tupolev (Kazan Aviation Institute), related to helicopter acoustics. The objective is to measure nar-field acoustics of rotors in hover and provide data suitable for computational fluid dynamics validation. The obtained set of data corresponds to a scaled rotor of known planform and the results are of high resolution. An advantage of the current dataset is that direct near-field acoustic data is made available and this allows for easy and direct comparisons with computational fluid dynamics predictions, without the need to use far-field aeroacoustic methods