凸台对多载荷AUV运载段阻力和流噪声的影响

Exploring Effect of Carrier Appendage on Drag and Flow Noise of Carrier of Multi-Load AUV

基于Smagorinsky亚格子应力模型的大涡模拟和Lighthill声类比的FW-H方程,分别对带凸台结构模型和原始模型进行了流场及声场的数值计算。通过分析凸台对流场及声场的影响,研究了凸台截面形状及尺寸减阻降噪机理。结果表明:凸台的存在对流场的分离产生了影响,抑制了涡的产生,进而形成减阻降噪效果;圆柱形凸台的长度和直径与减阻降噪效果之间具有一定的匹配关系,一定直径的圆柱其长度须达到一定的量值,才能起到较好的减阻降噪效果;半球形凸台的直径与其减阻降噪效果呈单调正比例关系。

After separation of loads from multi-load AUV （ autonomous underwater vehicle ） , the carrier did not have good hydrodynamic characteristics of the original shape of multi-load AUV.How to reduce the drag and flow noise of carrier has great significance .After carefully studying the ideas in Refs 4 and 5, we came to the idea of adding appendage to carrier , leading to the exploration mentioned in the title .This exploration is explained in sec-tion 1, 2 and 3, whose core consists of：“First, the LES （ Large Eddy Simulation ） with the Smagorinsky model and the FW-H equation based on Lighthill acoustic theory were adopted to simulate the flow field and the sound field of the carrier with different kinds of appendages .Then the drag and flow noise reduction mechanism of the appendages with different shapes and sizes was examined on the basis of the analysis of the flow field .” Numerical simulations are performed in section 3.The simulation results, given in Figs.5 through 12 and Tables 2 through 5, and their a-nalysis demonstrate preliminarily that：（ 1） the match between the length and diameter of the cylindrical appendage has effect on the drag and flow noise reduction; （ 2 ） the relationship between hemispherical appendage diameter and its drag and flow noise reduction effect is monotonically positive .Section 4 presents our preliminary main con-clusions, which we believe is helpful to the future design of multi-load AUV.