The dynamics of spheroidal masses of buoyant fluid
The dynamics of spheroidal masses of buoyant fluid
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浮力流体球体的动力学
DOI：
10.1017/s0022112064000854
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发表时间：
1964
影响因子：
3.7
通讯作者：
J. S. Turner
中科院分区：
文献类型：
--
作者：
J. S. Turner
它示出了如何一个简单的属性的球形涡模型可以用来调查的动态浮力，扩大热。不需要旋涡运动的细节，只需要知道围绕浮力区的流动是潜在的。主要结果是证明了在量纲分析中出现的两个常数C和α之间存在关系（在通常的记法中，w = C（Δr）1/2）和r = αz），这两个常数到目前为止一直被单独测量并被视为独立的。通过计算适当轮廓的虚质量，分析已扩展到球形热气流，并且还被推广到包括总浮力随时间增加的热气流。使用这些结果，和早期的实验验证，平均传播角几乎相同的各种条件下的稳定性，它建议，整个热的平均行为可以计算在两个几乎独立的步骤。首先，可以使用纯粹的运动学守恒方程来计算作为高度的函数的密度差或Δ。其次，速度是由Δ和半径r的局部值，使用C的平均值得到的，因为现在已经表明，在很宽的条件范围内，C的平均值变化很小。
It is shown how a simple property of the spherical vortex model can be used to investigate the dynamics of a buoyant, expanding thermal. No details of the vortex motion are required, only the fact that the flow round the buoyant region is potential. The main result is a demonstration that there is a relation between the two constants C and α arising in the dimensional analysis (where in the usual notation w = C (Δr) ½) and r = αz), which have up till now been measured separately and treated as independent. The analysis has been extended to spheroidal thermals by calculating the virtual mass for the appropriate outline, and it has also been generalized to include thermals in which the total buoyancy is increasing with time. Using these risults, and an earlier experimental verification that the mean angles of spread are nearly the same under various conditions of stability, it is suggested that the whole of the mean behaviour of a thermal can be calculated in two nearly independent steps. first, the density difference or Δ as a function of height may be calculated using purely kinematic equations of conservation. Secondly, the velocity is obtained from the local values of Δ and radius r, using a mean value of C, since this has now also been shown to vary little over a wide range of conditions.