Entraining gravity currents
Entraining gravity currents
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夹带重力流
DOI：
10.1017/jfm.2013.329
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发表时间：
2013
影响因子：
3.7
通讯作者：
Johnson C
中科院分区：
文献类型：
--
作者：
Johnson C
环境流体进入重力流的夹带，虽然在实验室规模的流动中通常可以忽略不计，但在大规模的自然流动中可能变得越来越重要。我们提出了一个理论研究，这种夹带的效果，通过增加一个简单的经验模型夹带下的深层环境下的重力流的浅水模型，根据实验测量的流体夹带率作为一个函数的散装理查森数。通过分析模型的长时间相似性解决方案，我们发现，在大理查森数的夹带系数的减少，由于抑制湍流混合的稳定分层，定性地影响的解决方案的结构和增长率，相比，在其中的夹带是恒定的或可以忽略不计的电流。特别是，混合是最显着的电流的前端附近，导致流动更稀释，更深，比他们的非夹带同行更慢。由稠密流体的锁释放产生的无粘卷吸重力流的长时间解是第二类相似解，其中流随时间的幂增长，这取决于卷吸定律的形式。与夹带法律，符合实验测量，在这个夹带无粘制度的电流的长度随时间的增长约为。在这两种情况下，夹带是最显着的电流前接近。
Entrainment of ambient fluid into a gravity current, while often negligible in laboratory-scale flows, may become increasingly significant in large-scale natural flows. We present a theoretical study of the effect of this entrainment by augmenting a shallow water model for gravity currents under a deep ambient with a simple empirical model for entrainment, based on experimental measurements of the fluid entrainment rate as a function of the bulk Richardson number. By analysing long-time similarity solutions of the model, we find that the decrease in entrainment coefficient at large Richardson number, due to the suppression of turbulent mixing by stable stratification, qualitatively affects the structure and growth rate of the solutions, compared to currents in which the entrainment is taken to be constant or negligible. In particular, mixing is most significant close to the front of the currents, leading to flows that are more dilute, deeper and slower than their non-entraining counterparts. The long-time solution of an inviscid entraining gravity current generated by a lock-release of dense fluid is a similarity solution of the second kind, in which the current grows as a power of time that is dependent on the form of the entrainment law. With an entrainment law that fits the experimental measurements well, the length of currents in this entraining inviscid regime grows with time approximately as . In both cases, entrainment is most significant close to the current front.
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影响因子：
3.7
作者：
B. M. Marino;L. P. Thomas;P. Linden
通讯作者：
P. Linden
分层流中的界面混合
影响因子：
2.3
作者：
G. Christodoulou
通讯作者：
G. Christodoulou
盐水楔的两层模型 I：夹带和界面摩擦。
影响因子：
2.4
作者：
M. Arita;G. Jirka
通讯作者：
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影响因子：
3.7
作者：
J. Gratton;C. Vigo
通讯作者：
C. Vigo
影响因子：
3.7
作者：
Hogg, AJ;Hallworth, MA;Huppert, HE
通讯作者：
Huppert, HE