COMPUTATIONAL MODELING OF HELICOPTER'S MAIN AND TAIL ROTOR INTERFERENCE ON THE BASE OF NON-LINEAR BLADE VORTICAL MODEL

摘要

Exploitation of single-rotor helicopters with tail rotor demonstrates that on some flight regimes tail rotor is highly influenced by vortical wake of main rotor. Under such circumstances changes of main rotor's aerodynamic characteristics become possible and they can lead to uncontrolled rotation of a helicopter.The paper contains some results of aerodynamic characteristics' computational modeling of main and tail rotor combination for a single-rotor helicopter with consideration of mutual interference between rotors.To solve the task of computational modeling non-linear blade vortical model with diffusion of free wake is used. Both this model and software created on its base for computational modeling of helicopter's rotors' aerodynamics were designed by the staff of Helicopter Design Department at the Moscow Aviation Institute (National Research University).A number of helicopter's flight regimes under which interference between rotors is demonstrated most of all and main rotor is highly influenced by vortical wake of main rotor was considered in the paper. The regime of helicopter's flight with low horizontal speed with cross wind (or flight with angle of slide) were considered.As a result of research for considered regimes a form of free vortical wake of main and tail rotor with consideration of their mutual interference was constructed, alsovisualization of rotor flowing was obtained and aerodynamic characteristics were calculated. The obtained data was estimated from the viewpoint of helicopter's safety and directional control.