中文摘要：

为了研究小口径武器的膛口气动噪声特性,采用CFD-CAA耦合算法对7.62 mm枪的射流噪声场进行了数值模拟.由于膛口流场结构复杂,在目前的计算发展水平下还不足以采用CAA直接法,因而本文中采用混合方法,即首先采用CFD方法计算7.62 mm枪的膛口流场,然后利用所得结果,采用声学方程计算射流噪声,具体为膛口近场采用LES进行计算,远场声场采用FW-H声拟法计算.通过对比验证实验,验证了该计算方法的可行性.然后,对7.62 mm枪射流噪声进行了数值模拟,分析了噪声指向性,绘制了声压级云图.研究表明：在本文的计算条件下,射流噪声强度主要集中在近膛口区域;且射流最大噪声主要分布在与轴线方向成30°～60°范围内。

英文摘要：

In order to investigate the characteristics of muzzle noise,a numerical study on jet noise induced by complex flows discharging from 7.62 mm gun is achieved.Because of the complex flows structure,it is not easy to study muzzle noise by direct simulation of CAA in current level of computational condition.CFD-CAA hybrid method is applied.At first,the muzzle flow is calculated by using LES.Using the obtained data,the jet noise is carried out by using FW-H equation.The feasibility of the numerical method is verified by comparing with the experiment.Then,the jet noise of 7.62 mm gun is numerically studied by using the hybrid method.Based on the numerical results,the jet noise directivity is analyzed and the contour of sound pressure level is also drawn.Results indicate that jet noise is mainly concentrated in the near muzzle region and the maximum jet noise mainly occurs in the range of 30°-60°.