关键词: Ffowcs Williams-Hawkings方程, 机轮, 起落架, 气动噪声, 圆柱体

Abstract: The civil aviation big plane is being developed in China. The noise level is a key factor to decide the airworthiness certificate ratification. On landing, the landing gear noise has become the major noise contributor for the total aircraft noise. Based on experimental data, a new numerical computational method for predicting aircraft landing gear noise is developed. In this method, the landing gear is divided into main parts, including cylinders and wheels. Then noise prediction models for every kind of parts are proposed by using the Ffowcs Williams-Hawkings equation. Finally, summed the noise of the different parts, the the total radiation noise of the landing gear can be obtained. The noise of landing gears with several wheels can be calculated by the new wheel model in the method, so the incorrect results by the simple wheel model in existing numerical methods can also be avoided. Based on the simulation data of the cylindrical directivity, the new model for calculating the directivity is proposed in the method. The model can be used to solve the problem of wrong directivity calculated in the existing numerical methods. Furthermore, the method can identify which part is the main noise source for the total radiation noise of the landing gear. The method can provide the technical support for designing the low noise land gear.

Key words: Aeroacoustic noise, Cylinder, Ffowcs Williams-Hawkings equation, Landing gear, Wheel