| 1. | Flow noise scaling at the stagnation point of an axisymmetric body 回转体驻点处的流噪声相似律 |
| 2. | Flow noise elimination for all optic towed arrays is one of the key technologies for fiber optic hydrophone 光纤水听器拖曳阵流噪声抑制是光纤水听器实用化的关键技术之一。 |
| 3. | ( 5 ) the near field and radiation field of flow noise are analyzed , and the noise reducing features of riblets are deduced ( 5 )在分析流噪声的近、远场特性的基础上,进一步研究条纹表面的降噪特性。 |
| 4. | Acoustics - laboratory measurement procedures for ducted silencers and air - terminal units - insertion loss , flow noise and total pressure loss 声学.管道消音器和气体终端设备的实验室测量步骤.插入损失流动噪声和总压损失 |
| 5. | Acoustics - laboratory measurement procedures for ducted silencers and air - terminal units - insertion loss , flow noise and total pressure loss 声学.管道消音器和空气终端装置的实验室测量步骤.插入损失流动噪声和总压损失 |
| 6. | Acoustics - laboratory measurement procedures for ducted silencers and air - terminal units - insertion loss , flow noise and total pressure loss iso 7235 : 2003 ; german version en iso 7235 : 2003 声学.管道消音器和空气界面装置的实验室测量步骤.插 |
| 7. | Flow noise elimination of this hydrophone is not revolved . the sensing sound model of the extended hydrophone is developed based on the principle of the ordinary fiber optic hydrophone 本文对这种成组光纤水听器的特性展开深入的理论和实验研究,不涉及流噪声抑制方面的讨论。 |
| 8. | The results of the experiment prove that both the model of the extended hydrophone sensing sound signal and the theoretical analyze based on the model are right . this is an important step for the research on the flow noise elimination of the extended fiber optic hydrophone towed array 成组光纤水听器理论分析和实验结果的一致性,证实了成组光纤水听器信号拾取模型和研究方法的正确性,为进一步开展成组光纤水听器流噪声抑制的研究奠定了基础。 |
| 9. | In the thesis the low drag - low noise optimization of the vehicle main form design is realized , main accomplishments are as follows . researched the knowledge of drag and flow noise , the parameters of the boundary layer are calculated by the hess - smith method and boundary layer momentum integral method . the calculation of the length of transition zone and change in boundary layer displacement thickness between laminar and turbulent states in the transition is improved , then the drag coefficient and self - noise from the transition zone are calculated as the objective functions of the optimization 主要研究内容和成果如下:对航行器绕流流场进行分析,深入研究了阻力和流噪声产生机理,建立了阻力系数和自噪声的评估数值计算模型;采用物面分布源汇法和边界层动量积分法对绕流流场的流体动力参数进行计算,改进了转捩区长度和边界层位移厚度的计算,应用于航行器头部驻点自噪声的计算;最后设计了阻力系数和自噪声数值计算程序模块。 |
| 10. | The porous diffusion type silencer is widely used to reduce the air flow noise because of its small volume and high noise attenuating ability . the out case of the silencer plays a very important role in reducing noise . the effect of the hole ' s shape , diameter and the distance between neighboring holes as well as the matchup between the case and the sound absorbing material tube are investigated experimentally . the relation between the out - flow noise and the gas velocity distribution is carefully studied for two different kinds of matchup between the case and the sound absorbing material tube . some useful results are gotten , which may be valuable to the design of the silencer 多孔扩散型消声器由于其体积小、消声性能高而广泛应用到排气噪声的降低上,其外壳对消声器的消声性能具有重要作用.本文对此类消声器外壳的孔型、孔径和孔距以及外壳同消声材料的配合方面进行了细致的实验研究,特别对外壳与消声材料的配合与其排放噪声以及外部流场之间的关系进行了探讨,得到了一些有用的结论,对消声器性能的提高具有一定指导意义。 |