A method and system for reducing rotor noise based on trailing edge flaps

Abstract

The invention discloses a method and a system for lowering rotor wing noise on the basis of a trailing edge flap. The method comprises the following steps that: obtaining the rotor wing parameter andthe working parameter of a helicopter; obtaining a first rotor wing thickness noise characteristic on an observation point; obtaining a plurality of second rotor wing thickness noise characteristics on the observation point; determining a target function, wherein the target function is a function which enables the area of a denoising region of the observation point to be maximum; according to thetarget function, determining the distribution position of applied external force; according to a sound field compensation method, determining the numerical value of the external force; adopting a CFD(Computational Fluid Dynamics) numerical value simulation method to determine a function relationship between the deflection parameter and the external force of the trailing edge flap; according to the function relationship between the deflection parameter and the external force and the numerical value of the external force, determining the deflection parameter of the trailing edge flap of the distribution position; and according to the deflection parameter of the trailing edge flap, regulating the deflection of the trailing edge flap on the distribution position so as to lower the rotor wingnoise of the helicopter. By use of the method and the system provided by the invention, the area of the denoising region of the rotor wing thickness noise can be obviously increased, and a denoising effect is improved.

Description

technical field [0001] The invention relates to the field of helicopters, in particular to a method and system for reducing rotor noise based on trailing edge flaps. Background technique [0002] With the wide application of helicopters in military and civilian fields, the serious disadvantage of helicopter noise radiation has attracted more and more attention, and has become a problem that needs to be considered in the process of helicopter design. Rotor noise is the most important part of helicopter noise. According to the formation principle, it can be divided into thickness noise, load noise, propeller-vortex interference noise and high-speed pulse noise. Among them, the thickness noise of the rotor mainly propagates outward along the plane of the paddle disc, and has many low-frequency components, so the thickness noise has the characteristics of slow attenuation and long propagation. The main composition of noise is a key factor affecting the performance of acoustic s...

AI Technical Summary

Problems solved by technology

Some researchers have reduced the rotor noise to a certain extent by optimizing the design of the rotor, such as reducing the rotating Mach number, changing the blade shape design (swept tip, tapered blade or thin airfoil), etc., but there are the following Disadvantages: 1) While reducing noise, it also affects the aerodynamic performance of the rotor, and a compromise needs to be made between noise and performance design; 2) There is no targeted noise reduction of rotor thickness noise, resulting in poor noise reduction effect of thickness noise ; 3) This passive noise control method also has the adaptability problem for different flight states, and the helicopter noise reduction under the full-envelope flight state cannot be realized.

In terms of active control, it mainly focuses on the control of rotor propeller-vortex interference noise. Regarding the noise reduction of rotor thickness noise, the existing method uses a separate external force on the tip of the rotor to cancel and reduce the noise of the rotor noise, which can only achieve noise reduction at a single control point. , the noise reduction area is small, the overall noise reduction effect is poor, and it is difficult to meet the noise reduction requirements in actual flight

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