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快速声散射方法(FSM)是一种基于无流动Helmholtz方程边值问题的声散射预测工具,具有快速、灵活的特点。以航空发动机消声短舱的声学设计为背景,用该方法对变截面管道声传播特性进行数值模拟研究,用直接边界元方法(DBEM)进行数值求解,避免了求解管口反射系数,有效地提高了计算速度。数值研究了刚性壁面和不同位置壁面声衬组合对变截面圆环管道形状声传播的影响,并分析了管道厚度对散射声场的影响,数值结果与声类比方法结果进行了相互验证。最后,还对一种真实转子声源进行了管道声散射的数值研究,结果表明本方法在航空发动机声学设计中具有工程应用价值。
Fast Acoustic Scattering (FSM) is an acoustic scattering prediction tool based on the boundary value problem of the non-flow Helmholtz equation, which is fast and flexible. Taking the acoustical design of aeroengine anechoic nacelle as the background, this method is used to study the numerical simulation of acoustic propagation in a variable cross-section pipe. The direct boundary element method (DBEM) is used to solve the problem numerically, which avoids solving the nozzle reflection coefficient effectively Increased computational speed. The effect of the combination of rigid wall and wall lining in different positions on the sound propagation of circular pipe with variable section was numerically investigated. The effect of pipe thickness on the sound field was analyzed. The numerical results were verified with the results of acoustic analogy. Finally, a numerical study on the pipe sound scattering of a real rotor sound source is also carried out. The results show that this method is of engineering value in the acoustic design of aeroengine.