Laser-Assisted Prediction of Acoustic Radiation and Scattering

肖恩·F Wu，P.I.韦恩州立大学NSF提案号0084723激光辅助预测声辐射和散射项目摘要本研究旨在开发一种高度准确和有效的方法来预测任意物体的声辐射和散射。一种非侵入式三维激光多普勒测速仪（LDV）是用来扫描和测量的速度矢量的悬浮颗粒在一个控制表面，完全封闭的结构在考虑中的声穿透流体介质。测量的速度矢量作为输入显式积分公式计算声压场。这种方法的上级之处在于：（1）它将场声压直接与质点速度分布相关联;（2）它提供了所有频率下声压的唯一解;（3）它使人们能够方便地解决瞬态声辐射问题。这种新技术可以应用于预测任何结构的声辐射和散射。特别地，它适用于柔性或轻质结构，或者不允许传统接触式测量装置的结构。该项目由韦恩州立大学机械工程系和电气计算机工程系联合开展。这项联合研究对计算声学产生了深远的影响。它有望彻底改变目前计算任意物体声辐射和散射的方法，并显着提高数值计算的效率。这对于必须考虑流体载荷效应的复杂结构尤其如此。这种新技术的应用可以在水下或地面车辆产生的声场分析中找到。使用这种新方法，工程师可以评估噪音传输到飞机机舱或车辆乘客舱的性能，或车辆经过的噪音水平。由此获得的知识将使他们能够以具有成本效益的方式处理飞机和车辆的振动和噪音问题。

Sean F. Wu, P.I.Wayne State UniversityNSF Proposal No. 0084723Laser-Assisted Prediction of Acoustic Radiation and ScatteringProject AbstractThis research aims at developing a highly accurate and efficient methodology for predicting acoustic radiation and scattering from an arbitrary object. A non-invasive three-dimensional laser Doppler velocimetry (LDV) is used to scan and measure velocity vectors of suspended particles in an insonified fluid medium over a control surface that completely encloses the structure under consideration. The measured velocity vectors are taken as input to an explicit integral formulation to calculate the acoustic pressure field. This methodology is superior in that: (1) it correlates the field acoustic pressure directly to the particle velocity distribution; (2) it provides unique solutions for acoustic pressures in all frequencies; and (3) it enables one to solve transient acoustic radiation problems conveniently. Applications of this new technology can be found in predicting sound radiation and scattering from any structure. In particular, it is suitable for a flexible or lightweight structure, or for a structure that does not allow for conventional contact measurement devices. This project is carried out jointly between Mechanical Engineering Department and Electrical & Computer Engineering Department of Wayne State University. This joint research has a far-reaching impact on computational acoustics. It is expected to revolutionize the current way of calculating acoustic radiation and scattering from an arbitrary object, and significantly improve the efficiency in numerical computations. This is especially true for a complex structure for which the fluid-loading effect must be considered. Applications of this new technology can be found in the analyses of the sound field generated by an underwater or ground vehicle. Using this new method, engineers can assess the performance of noise transmission into an aircraft cabin or vehicle passenger compartment, or vehicle pass-by noise levels. The knowledge thus gained will enable them to tackle aircraft and vehicle vibration and noise problems in a cost-effective manner.