论文标题
与粗糙度阵列相互作用的穿流重力电流的瞬态行为
The transient behaviour of through-flowing gravity currents interacting with a roughness array
论文作者
论文摘要
我们提出了研究重力电流的结构和流动特性，这些实验室的重力电流的结构和流动特性。粗糙度元素的高度与重力电流相当，因此电流流过粗糙度阵列而不是越过它。额叶速度和密度结构被测量为从光滑的床流向流过粗糙度阵列的电流过渡，然后回到光滑的床。我们发现，进入粗糙度阵列后，重力电流减速，密度结构从典型的光滑床重力电流的头部和尾巴结构变化为楔形。提出了一个模型，该模型根据当前尾巴内的压力梯度与与单个粗糙度元素相关的阻力梯度之间的动态平衡来解释减速和形状的变化。该模型准确地预测了重力电流的减速，从而支持提出的动态平衡。
We present laboratory experiments that investigate the structure and flow characteristics of gravity currents travelling through an array of roughness elements. The roughness elements are of comparable height to the gravity current such that the current flows through the roughness array rather than over it. The frontal velocity and density structure are measured as the current transitions from flowing along a smooth bed to flowing through the roughness array, and then back to a smooth bed. We find that, upon entering the roughness array, the gravity current decelerates and the density structure changes from the head and tail structure typical of smooth bed gravity currents, to a wedge shape. A model is presented that explains the deceleration and change in shape based on a dynamic balance between a pressure gradient within the current tail and a drag force associated with individual roughness elements. This model accurately predicts the deceleration of the gravity current, supporting the proposed dynamic balance.
