【作者】 张博；

【导师】 商德江；

【作者基本信息】 哈尔滨工程大学 ， 水声工程， 2016， 硕士

【摘要】 流噪声是水下航行器高速航行时的主要噪声源,如何有效的降低流噪声,对航行器的声隐身效果来说十分重要。水下开口腔结构会产生极大的流噪声而成为航行器减振降噪所关注的重要课题。本文先后以水下航行器发射舱模型和水下航行器指挥台围壳模型为研究对象,利用CFD软件Fluent与声学计算软件ACTRAN等多种流噪声计算软件,采用大涡模拟湍流模型与lighthill声类比理论、有限元、无限元相结合的方法研究了其流噪声特性。针对发射舱,建立闭口的以及平行来流方向开口的两种不同开口数量的发射舱缩比模型,数值仿真计算了处在两种流速下各模型的流场结果。得到了各流速下模型表面压力云图,速度云图,涡粘性云图,脉动压力云图并加以分析;在此基础上,对航行器发射舱模型振动声辐射特性进行了研究,计算并分析了航行器驻点、艇艏附近及发射舱内频谱特性以及流速和来流攻角对航行器发射舱模型振动与声辐射的影响规律。针对指挥台围壳,建立封闭的、垂直来流方向开口的和开口外贴吸声覆盖层材料的航行器指挥台围壳缩比模型,进行了流噪声数值仿真计算研究并分析了其流噪声频谱特性与流噪声指向性特点;并针对三种不同的来流速度研究其流噪声的变化规律;给出了由于开口以及敷设吸声覆盖层材料对航行器指挥台围壳模型流噪声的影响。最后设计加工了与数值仿真计算中相同的指挥台围壳试验模型,在水声技术实验室重力式水洞应用混响箱法对其进行了流噪声测量,验证了数值仿真计算的正确性。更多还原

【Abstract】 Flow noise is the main noise source of underwater vehicle at high speed. Thus, it is very important to study how to effectively reduce the flow noise for sound stealth of underwater vehicle. Underwater open cavity, which can induce great fluid noise, becomes an important issue to reduce the underwater vehicle vibration and noise. This paper focuses on the characteristics of flow noise by underwater vehicle launch compartment and sails. The Large Eddy Simulation method combined with Lighthill’s acoustic analogy theory, finite element method and infinite element is used by software FLUENT and ACTRAN to simulate the underwater flow noise.The launch compartment models are built up in two cases, case1: the cabin has no opening, case 2: the launch compartment has two different numbers of openings parallel to the flow direction. The flow noise frequency characteristics and its far field pattern are calculated and analyzed for different flow speed. The cloud pictures of surface pressure, velocity and eddy viscosity and fluctuating pressure diagram from various opening models are obtained and analyzed by numerical simulation; vibration and sound radiation spectral characteristics in underwater vehicle stations, near the bow vehicle and in the launch compartment are also calculated and analyzed; the effect of flow speed and attack angle on underwater vehicle launch compartment and acoustic radiation is discussed.We established three underwater vehicle sail models, model 1: without opening, model 2:with a opening vertical flow direction, model 3: with a opening and anechoic coating material on outside surface. The flow noise frequency characteristics and its far field pattern are calculated and analyzed for these models by numerical simulation for three different inflow speed; The effect of the opening and anechoic coating material on underwater vehicle sail flow noise is also analyzed. then, the experimental sail model with the same size as that in numerical simulation is designed and fabricated, and its flow noise is measured by reverberation chamber method in gravitational water tunnel of underwater acoustic technology laboratory. The experimental results show the correctness of numerical simulation calculations.更多还原