Laboratory experiments are conducted to examine a descending plume in a rotating two-layer stratified ambient fluid such that the plume at the interface has moderate to large Rossby number. While the source fluid is more dense than the lower layer, the experiments are designed so that the mean density of the plume fluid impinging upon the interface is less than the lower layer density, as represented by a buoyancy parameter, \(\varLambda \), being less than unity. In such cases, the discharged plume fluid spreads radially at the interface in the form of an intrusive gravity current at early times. At later times, this intrusion evolves to form an anticyclonic lens due to the influence of the Coriolis force. The measured radial position of the intrusion front, R(t), follows different power law relationships at early and late times during the spread of the intrusion: at early times when rotation does not play a significant role the power law exponent lies between 0.5 and 1.1; at late times when the intrusion acts as a rotationally influenced expanding lens the power law exponent ranges between 0.15 and 0.5, with generally smaller values for larger \(\varLambda \). The plume fluid reaching the interface progressively increases in density due to re-entraining relatively dense fluid as the plume descends within the thickening lens. Consequently, the plume eventually penetrates through the interface and descends to the bottom of the tank. Faster rotation makes the lens thicker and hence increases the volume of the re-entrained lens-fluid, which decreases the time for the onset of penetration. The penetration time normalized by the rotation rate is found to hold a simple power law relationship with \(\varLambda \).

中文翻译：

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旋转的两层分层流体中的羽状物

进行实验室实验以检查旋转的两层分层环境流体中的下降羽流，以使界面处的羽流具有中等到较大的Rossby数。尽管源流体比下层致密，但设计实验时应使撞击在界面上的羽状流体的平均密度小于下层密度，如浮力参数\（\ varLambda \）所示。，不够团结。在这种情况下，排出的羽状流体在早期以侵入重力流的形式在界面处径向扩散。在以后的时间里，由于科里奥利力的影响，这种侵入演变成反气旋透镜。测得的侵入前沿的径向位置R（t）在入侵蔓延的早期和晚期遵循不同的幂定律关系：在轮换没有显着作用的早期，幂定律指数在0.5和1.1之间；在后期，当入侵物作为受旋转影响的扩展透镜时，幂律指数在0.15和0.5之间，对于较大的\（\ varLambda \），通常较小的值。由于随着羽流在增稠透镜内下降而重新夹带相对致密的流体，到达界面的羽流流体的密度逐渐增加。因此，羽流最终穿过接口并下降到水箱底部。更快的旋转会使晶状体变厚，从而增加了重新夹带的晶状体液的体积，从而缩短了渗透开始的时间。发现通过转速归一化的穿透时间与\（\ varLambda \）保持简单的幂律关系。