沿加热壁面推进的重力流锋面
Gravity current fronts advancing along a heated wall
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中文总结 AI 辅助
本研究通过实验室实验结合集总分析模型，探究沿加热壁面推进的重力流锋面的传播规律，明确了锋面速度受Λ_s等因素控制，揭示了加热对锋面减速及最终停滞的影响机制。
中文摘要 AI 辅助
本研究通过实验室实验探究沿加热壁面推进的持续布辛涅斯克重力流锋面的传播规律。重力流由矩形通道入口处持续供应空气与二氧化碳的混合物产生，壁面的均匀加热通过电阻织物实现。除弗劳德数（定义为源处的Fr_s或锋面处的Fr）外，研究表明锋面速度由Λ_s控制，Λ_s是驱动流动的两个单位面积浮力通量的比值：一个是壁面加热产生的浮力通量，另一个是入口供应的浮力通量。随着壁面加热增强（即Λ_s增大），重力流锋面的推进速度减慢，这种减速源于壁面对重力流的直接加热，降低了其头部的浮力，以及锋面与下游自然对流产生的热羽流之间的相互作用。在加热最强的实验中，锋面最终会在距源的某一距离处停止，该距离与Λ_s成反比；此时重力流头部的浮力符号发生改变，演变为正浮力羽流，其垂直范围持续增大。研究将实验结果与集总分析模型的预测进行了对比，该模型描述了重力流的传播及最终停滞过程。
英文摘要
The propagation of sustained Boussinesq gravity-current fronts along a heated wall is examined through laboratory experiments. The gravity currents are generated by continuously supplying a mixture of air and carbon dioxide at the inlet of a rectangular channel, while uniform wall heating is provided by resistive fabrics. In addition to the Froude number, defined either at the source (Fr_s) or at the current front (Fr), we show that the front velocity is governed by Λ_s, the ratio of the two buoyancy fluxes per unit area driving the flow: that generated by wall heating and that supplied at the inlet. As wall heating increases (i.e., as Λ_s increases), the current front propagates more slowly. This slowdown results from the direct heating of the current, which reduces the buoyancy of its head, and from the interaction between the front and the thermal plumes generated by natural convection downstream. In the most strongly heated experiments, the front eventually stops at a distance from the source that is inversely proportional to Λ_s. In these cases, the buoyancy of the head changes sign, and the head evolves into a positively buoyant plume whose vertical extent continues to increase. The experimental results are compared with predictions from a lumped analytical model describing the propagation and eventual arrest of the current.
