空泡

The CFD method was applied to calculate and simulate the form and action process of the cavitation at the representative character of the cavitation erosion on the surface of the hydraulic turbines.Some argumentation was presented that micro jet impacted the wall with a certain degree when bubble collapsed with the result that the maximal strain of the wall annularly distributed the local of the boundary touching the micro jet.Cavitation was gradual to develop regionally at the mode of chain reaction and di...

针对水轮机叶片表面气蚀的典型特征，利用CFD方法进行仿真计算，模拟气蚀形成和作用过程；根据模拟计算结果提出了新观点：空泡溃灭发生微射流以一定的倾角冲击壁面，壁面材料产生的最大应变在流束边界局部区域，呈环状分布；空泡气蚀在局部区域是渐进的，以"连锁反应"形式扩展，具有一定过流环境的分布特征；典型的冲蚀缺陷形貌是空泡气蚀在不同阶段的产物。

Employing the finite difference calculus, the cavitation bubble pulsating performance with the change of liquid viscosity, gas content, surface tension and condensability is obtained.

在系统地研究固壁面附近空泡溃灭过程的基础上，提出并研究了射流阈值、空泡在第一次和第二次脉动过程衰减蚀除机理以及空泡溃灭周期延长因子等问题。

Based on the theory of cavitating flows,the definition of supercavitation ,the main idea of reducing drag by ventilated cavitation and the principle of supercavitation torpedo are introduced.

文章从空泡流理论出发，介绍了超空泡的定义、超空泡减阻的基本思想和超空泡鱼雷的工作原理，并分析了超空泡技术研究中的关键问题和未来发展趋势

It gives up the unreasonable spherical hypothesis which is out of accord with the reality.

考察了不同壁面、空泡离壁面的距离和空泡的气体含量对空泡演化及辐射噪声的影响，该方法将边界元方法得到的空泡演化情况与声学方程在特殊情况下的解结合起来，放弃理论分析上不合理的球形假设，并考虑了边界的影响，这样更符合实际的空化现象，得到了与实验相一致的结论。

Mol·L~(-1) individually and also with both heavy metals present. Plasmolysis, concentrated cytoplasm, disappear ance of the cristae of mitochondria, ambiguity of framework and destruction of mitochondria envelope were all symptoms of root cells under Cu stress; hollowing cells was also found in Cd treatment, and there existed some different granule in these hollowing cells.

铜使根细胞产生质壁分离、细胞质浓缩、部分细胞空泡化，使线粒体脊突消失、结构模糊、外膜破坏；镉使根细胞空泡化，并在部分空泡化的细胞里产生大小不等的颗粒状物；铜、镉交互污染使根细胞受害程度加深，并兼有两者的受害症状特征：线粒体结构彻底破坏、空泡化细胞里的颗粒物更大电子密度更高、质壁分离现象更普遍、质膜上的颗粒物沉淀更大。

This paper briefly introduces the current development of supercavitating torpedoes in the world,and explains some confusable terms,including cavity,supercavitation, natural supercavitation ,air supercavitation and cavity number.

在简要回顾各国超空泡鱼雷发展概况的基础上，解释了几个易混淆的与空泡有关的新术语(空泡、超空泡、自然超空泡、通气超空泡和空泡数)，分析了超空泡的形成机理和特点，详细阐述超空泡鱼雷在总体结构和性能、动力推进、控制系统和弹道形式等方面的技术特点，概括超空泡鱼雷与普通鱼雷在结构外形、流体动力布局、系统组成和工作特性等方面的不同之处。

The growth of bubble cloud experiences swelling and compressing, reinflating and recompressing, collapsing and falling in the cavitation water jets or abrasive water jets with bubble.

在纯水空化射流与低浓度的磨料射流中，空泡云的发育过程经历了空泡云的膨胀、压缩、再膨胀、压缩、溃灭的几个过程。

Themotion equations of a bubble near a plane wall have been established with the lift forceand wall effects on the drag force taken into consideration.

我们在全面考虑壁面对空泡运动粘性阻力和升力影响的基础上，建立了空泡在近壁区内的运动方程，计算结果表明由于壁面的存在将阻滞空泡沿水流方向和垂直水流方向上的运动，即有滞留空泡在空化形成点，减缓空泡逸离空泡发生区的作用。

Based on Wavelet Packet Analysis and Smoothed Pseudo Wigner-Ville Distribution, the experiment data is time-frequency analyzed. The experimental results indicate that the amplitude of the laser-induced acoustic waves increases with the laser energy; the frequency coverage is from 0 to 150 KHz, and in the meantime there is a peak located at about 25 KHz. In addition, the spectrum and the peak of frequency are basically stable in spite of the change of laser energy and target texture.

从基本的空泡动力学理论出发，推导了空泡各特征参量之间的关系，进而对空泡动力学模型进行了修正；采用有限差分法对空泡脉动进行数值模拟，得到了空泡脉动特性随液体粘性、空泡含气量、表面张力以及可压缩性的变化规律；实验上采用光偏转测试装置探测了激光空泡脉动以及空泡溃灭的细节过程，进而分析了液体粘性和作用激光能量对空泡脉动周期、泡半径及泡能等特征参数的影响。

Assuming fluid is and viscid and slightly compressible, bubble collapse near rigid boundary and free surface is simulated, displaying characteristics such as formation, penetration and impact of reentrant jet as well as vortex ring and bubble rebound.

采用粘性、微可压流体模型，数值模拟了空泡在刚性边界和自由面附近溃灭及空泡溃灭后流动的发展，显示了空泡溃灭过程中的凹陷射流形成、空泡贯穿、射流冲击、涡环的形成和空泡回弹等流动特征，提出空泡回弹的另一种机制是凹陷射流冲击形成的旋涡。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。