Experiments on the penetration of an interface by buoyant thermals
Experiments on the penetration of an interface by buoyant thermals
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浮力热气流穿透界面的实验
DOI：
10.1017/s0022112061000585
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发表时间：
1961
影响因子：
3.7
通讯作者：
J. M. Richards
中科院分区：
文献类型：
--
作者：
J. M. Richards
孤立的大量稠密水溶液（即热气流）在覆盖盐水层的淡水层表面释放。当整个热气流保留在上层时，方程 $z = n_1r, \; z^2 = k_1t$，其中 $k_1 = C_1 n_1^{\frac {3}{2}}(Mg| \rho)^{\frac {1}{2}}$，其中 z 是行进距离，2r 是热流宽度，t 是经过时间，M 是过剩质量（上层热流所包含的质量和被热流取代的质量之间的差值），ρ 是被驱替流体的密度。 n1 对于任何一股热气流都是恒定的，但在 1·9 到 7·5 范围内的热气流之间变化。所有热气流的 C1 值大致相同 (0·73)。热气流的前端（“前部”）进入下层后的行为取决于参数 S = Vρ/M 的值，其中 Δρ 是上层和下层之间的密度差，V 是当最宽部分位于间断层时热气流的体积。研究发现，如果 S = β（“弱”热气流），则 Y = 0；如果 0·1 < S [les ] β（“强”热气流），则 Y = 0·95−½S，其中 Y 是无限期渗透到下层的释放物质的质量分数。常数β约等于1.90。在弱热气流中，锋面处于下层时，遵循方程 z − s = a1(t − ts)2，直到在 t = ts 时达到聚光点 z = s。加速度 a1 始终为负值，并且对于任何一股热气流都是恒定的，但在热气流之间有所不同。同样对于弱热气流，$x = C_2 V^{\frac {1}{3}}|S$，其中 x 是从界面到顶点的距离，C2 是常数。 C2约等于3·5。对于强热气流，锋面位于下层时移动的距离遵循方程 z2 = k2t。 z和t的起源通常与上层的起源不同，并且通常k2≠k1。
Isolated masses of a dense aqueous solution (i.e. thermals) were released at the surface of a freshwater layer overlying one of salt water. While the whole of a thermal remained in the upper layer, the equations $z = n_1r, \; z^2 = k_1t$, with $k_1 = C_1 n_1^{\frac {3}{2}}(Mg| \rho)^{\frac {1}{2}}$, were obeyed, where z is the distance travelled, 2r the width of the thermal, t the elapsed time, M the mass excess (the difference between the masses contained within and displaced by the thermal while in the upper layer), and ρ the density of the displaced fluid. n1 was constant for any one thermal, but varied between thermals over the range 1·9 to 7·5. C1 had roughly the same value (0·73) for all thermals. The behaviour after the leading extremity of the thermal (the ‘front’) entered the lower layer depended on the value of the parameter S = Vρ/M, where Δρ is the density difference between the upper and lower layers and V is the volume of the thermal when the widest part is at the level of the discontinuity. It was found that Y = 0 if S = β (‘weak’ thermals), and Y = 0·95−½S if 0·1 < S [les ] β (‘strong’ thermals), where Y is the fraction of the mass of the substance released which penetrated indefinitely into the lower layer. The constant β was approximately equal to 1.90. In weak thermals, the equation z − s = a1(t − ts)2 was obeyed while the front was in the lower layer, until the cluminating point z = s was reached at t = ts. The acceleration a1 was always negative, and constant for any one thermal, but varied between thermals. Also for weak thermals, $x = C_2 V^{\frac {1}{3}}|S$, where x is the distance from the interface to the culminating point and C2 is a constant. C2 was approximately equal to 3·5. For strong thermals, the distance travelled while the front was in the lower layer obeyed the equation z2 = k2t. The origins of z and t usually differed from those found in the upper layer, and generally k2 ≠ k1.