基于尾跡分析的旋翼旋轉(zhuǎn)噪聲計算及槳-渦干擾噪聲研究.pdf

1、南京航空航天大學(xué)博士學(xué)位論文基于尾跡分析的旋翼旋轉(zhuǎn)噪聲計算及槳-渦干擾噪聲研究姓名：宋辰瑤申請學(xué)位級別：博士專業(yè)：飛行器設(shè)計指導(dǎo)教師：徐國華2010-02基于尾跡分析的旋翼旋轉(zhuǎn)噪聲計算及槳-渦干擾噪聲研究 II Abstract Rotor noise is a challenging subject in the field of helicopter aerodynamics. Based on wake analysis, on

2、one hand, the computational method for rotor rotational noise in hover and forward flight and the effect of parameters are investigated in this thesis. On the other hand, the detective method on blade-vortex interaction

3、and directionality of its noise in the near/far field and radiation intensity are deeply analyzed. Also, the radiation characteristics about BVI noise of modern rotors with new blade tips and parameter influences are inv

4、estigated. The major contributions of the author’s research work are as follows: As the background of present work, the objectives of the research are firstly described. The research and development in the field of the h

5、elicopter rotor rotational noise, blade-vortex interaction sources detection, directionality and radiation characteristic of BVI noise, as well as wake analysis are briefly introduced. The difficulties in the current res

6、earch on the BVI noise are pointed out. In addition, the methods used in the present research are briefly introduced. In order to provide an accurate airfoil aerodynamic model for computation of the rotor aerodynamic loa

7、ding and noise, Chapter 2 establishes a method of computing airfoil unsteady aerodynamic forces at the attached flow, separated flow and stalled flow, based upon the Leishman-Beddoes model. The comparisons with the avail

8、able experimental data are also made to show the capability of the method. Aiming at rotational noise computation and BVI detection, a free-wake model for hover and forward flight rotor is presented. By using this model,

9、 the free-wake geometry, induced inflow and loading distribution of the rotor at different advance ratios are calculated for validation purposes. By employing Farassat Acoustic Formula 1A in the time domain and combining

10、 the free-wake model, a numerical method of rotational noise computation for hover and forward flight has been developed. By the method developed, both rotor thickness and loading noise are computed. The influence of dif

11、ferent design parameters on the rotational noise, such as rotor speed, blade number and rotor diameter, are also investigated. On the basis of the investigation, some meaningful results are obtained. Then, a new model fo

12、r studying BVI noise directionality and radiation characteristics at the advancing side and retreating side of a rotor is developed with the help of the Beddoes modified wake model. The distribution features of BVI noise

13、 at the rotor advancing side and retreating side are studied, and the effect of different parameters such as blade number, advance ratio and tip Mach number, are also analyzed. Some conclusions have been drawn from analy