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1.
Axisymmetric acoustic wave propagation in a shear pipeline flow confined by a rigid wall is studied in the two-part paper. The effects of viscous friction and thermal conduction on the acoustic wave propagating in the liquid and perfect gas are respectively analyzed under different configurations of acoustic frequency and shear flow profile. In Part 1 of this paper, mathematical models of non-isentropic and isentropic acoustic waves are formulated based on the conservation of mass, momentum and energy for both liquid and perfect gas. Meanwhile, comprehensive solutions based on the Fourier-Bessel theory are provided, which gives a general methodology of iteratively calculating features of the acoustic wave. Numerical comparisons with previous simplified models verify the validity of the proposed models and solutions.  相似文献   

2.
声波在含气泡液体中传播特性及产热效应*   总被引:1,自引:1,他引:0       下载免费PDF全文
袁月  苗博雅  安宇 《应用声学》2018,37(5):717-721
该文对含气泡液体中的声波方程采用线性分析方法,研究了超声波在含气泡液体中的传播特性以及产热效应。当声波在含气泡液体中传播时,气泡的存在会影响声波的传播,在声波频率接近气泡共振频率的频段内,声信号在液体中传播时剧烈衰减,而在声波频率远远高于或低于气泡共振频率时,声波的传播基本不受影响。在接近气泡共振的频段内,声波耗散的能量最终转化为热能。同时液体中的气泡会在声波驱动下径向振动并辐射声波,伴随气泡壁在液体中的粘滞振动,热量随之产生。结果表明,两种产热机制分别在不同频段起主导作用。  相似文献   

3.
Axisymmetric acoustic wave propagating in a shear pipeline flow confined by a rigid wall is studied in the two-part paper. The effects of viscous friction and thermal conduction on the acoustic wave propagating in the liquid and perfect gas are respectively analyzed under different configurations of acoustic frequency and shear mean flow. In Part 2 of this paper, comprehensive analysis of the effects of shear mean flow and acoustic frequency on the features (relative phase velocity and attenuation coefficient) of the acoustic wave are numerically addressed in cases of water and perfect gas respectively. Comparisons between the non-isentropic and isentropic models are provided in details. Meanwhile, discussions of the thermoviscous effects on the acoustic wave between water and perfect gas are given.  相似文献   

4.
基于竖直爆轰管和径向Hele-Shaw Cell, 设计并搭建了一套准二维柱面爆炸波加载装置, 可以实现对Hele-Shaw Cell内部材料界面的径向冲击加载. 竖直爆轰管内部的预混气体在底部点燃后, 形成向上传播的冲击波, 冲击波冲破爆轰管开口与Hele-Shaw Cell底板开孔之间的隔膜后, 被Hele-Shaw Cell的顶板阻碍, 形成在Hele-Shaw Cell内部径向传播的发散柱面波. 通过同步的高速摄影和压力测试系统, 可以获得Hele-Shaw Cell内部燃爆产物气体的膨胀过程, 同时将膨胀过程与Hele-Shaw Cell内部冲击压力演化过程相耦合. 实验发现Hele-Shaw Cell内部的柱面冲击波具有良好的可重复性和环向压力均匀性. 对燃爆过程和Hele-Shaw Cell内部的柱面波传播过程进行了CFD数值模拟, 当预混气体初始压力在100~250 kPa范围内时, 可获得超压峰值在400~3 000 kPa, 冲量在50~180 Pa·s,Ma为2.8~4.4的柱面波, 通过函数拟合得到了超压随径向传播距离呈幂函数衰减的规律, 揭示了爆轰管内的燃爆过程对Hele-Shaw Cell内部超压和冲量分布的影响. 研究发现, 通过调节燃爆过程和预混气初始条件可以实现对Hele-Shaw Cell内部冲击波加载参数的调控.   相似文献   

5.
We investigate the acoustic wave propagation in bubbly liquid inside a pilot sonochemical reactor which aims to produce antibacterial medical textile fabrics by coating the textile with ZnO or CuO nanoparticles. Computational models on acoustic propagation are developed in order to aid the design procedures. The acoustic pressure wave propagation in the sonoreactor is simulated by solving the Helmholtz equation using a meshless numerical method. The paper implements both the state-of-the-art linear model and a nonlinear wave propagation model recently introduced by Louisnard (2012), and presents a novel iterative solution procedure for the nonlinear propagation model which can be implemented using any numerical method and/or programming tool. Comparative results regarding both the linear and the nonlinear wave propagation are shown. Effects of bubble size distribution and bubble volume fraction on the acoustic wave propagation are discussed in detail. The simulations demonstrate that the nonlinear model successfully captures the realistic spatial distribution of the cavitation zones and the associated acoustic pressure amplitudes.  相似文献   

6.
The acoustic field and the field of radiative forces that are formed in a liquid layer on a solid substrate are calculated for the case of wave propagation along the interface. The calculations take into account the effects produced by surface tension, viscous stresses at the boundary, and attenuation in the liquid volume on the field characteristics. The dispersion equations and the velocities of wave propagation are determined. The radiative forces acting on a liquid volume element in a standing wave are calculated. The structure of streaming is studied. The effect of streaming on small-size particles is considered, and the possibilities of ordered structure formation from them are discussed.  相似文献   

7.
王勇  林书玉  张小丽 《物理学报》2014,63(3):34301-034301
考虑到分布在液体中的气泡是声波在含气泡液体中传播时引起非线性的一个很重要的因素,本文研究了声波在含气泡液体中的非线性传播.将气体含量的影响引入到声波在液体中传播的方程中,从而得到声波在气液混合物中传播的数学模型.通过对该模型进行数值模拟发现,气体含量、驱动声场声压幅值及驱动声场作用时间均会影响到气液混合物中的声场分布及声压幅值大小.液体中的气泡会"阻滞"液体中声场的传播并将能量"聚集"在声源附近.对于连续大功率的驱动声场来说,液体中的气泡会"阻滞"气液混合物中声场及其能量的传播.  相似文献   

8.
It is shown that the circumferential internal waves propagating around an elastic cylinder can be locally seen as plane evanescent waves, at any observation point inside the surrounding fluid. This is done by direct calculation of the associated complex bivector. The exact anatomy of the wave is detailed and the phase propagation paths are found to be curved, as expected. The transition to the plane interface is achieved. Polarization ellipses associated with the acoustic displacement vector are described. The additional low evanescence assumption leads to conventional ray interpretation with identification of the ray tube divergence coefficients, and the wavefront is found to be the involute of a circle.  相似文献   

9.
The dynamics and acceleration of an electron in the field of a transverse electric wave propagating inside a cold plasma-filled waveguide by microwave radiation is analytically investigated by considering the existence of a coaxial metallic rod. The relativistic momentum and energy equations are solved for the electron when it is injected along the direction of mode propagation. The deflection angle and the acceleration gradient of the electron in the configuration are obtained. Besides, the results are graphically presented.  相似文献   

10.
The objective of this paper is to apply both experimental and numerical methods to investigate acoustic waves induced by the oscillation and collapse of a single bubble. In the experiments, the schlieren technique is used to capture the temporal evolution of the bubble shapes, and the corresponding acoustic waves. The results are presented for the single bubble generated by a low-voltage bubble generator in the free field of water. During the numerical simulations, a three-dimensional (3D) weakly compressible model is introduced to investigate the single bubble dynamics, including the generation and propagation of acoustic waves. The results show that (1) Compression wave, rarefaction wave and shock wave are generated during expansion stage, collapse stage and rebound stage of the bubble respectively. (2) Compression waves are induced by the rapid expansion of the bubble and eventually steepen into one shock wave propagating outward in the liquid, then another strong shock wave is emitted at the final collapse stage. The velocity and pressure of the liquid field increases after the shock wave. (3) Rarefaction waves are generated during the collapse stage due to the contraction of the bubble. The rarefaction wave reduces the liquid pressure and its spatial distribution is dispersive. The pressure of these acoustic waves and their effect on the liquid velocity attenuate with the increase of propagation distance.  相似文献   

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