Motivated by the observation of sediments being carried by meltwater plumes originating at the base of a marine terminating glacier, laboratory experiments are performed to examine the transport and deposition of particles settling out from a buoyant line-plume rising along a sloping upper boundary. If the plume source has relatively high momentum and is located near the bottom of the domain, then a strong recirculating region develops near the source. Emanating from this region is a particle bearing buoyant plume that moves at near constant speed along the slope. Particles are observed to settle within the plume itself and then descend from the plume toward the tank bottom being drawn back in the direction of the source through a return flow driven by the plume's entrainment of the underlying ambient fluid. A light attenuation technique is employed to measure nonintrusively the depth of the sediment bed after the source is turned off and all the particles settled out. Sediments are found to accumulate near the source over the extent of the recirculating region and then decrease approximately linearly with distance from the source. Conceptual theoretical models suggest that the linearly sloping bed results from a combination of vertical mixing in the plume near the recirculation region and the return flow acting to detrain from the plume particles more effectively near the plume source where the shear between the plume and the return flow is largest. In many aspects the experiments are not representative of a steady glacial meltwater plume due to restrictions of the experimental setup, notably the relatively low Reynolds number of the flow. Nonetheless the experiments are suggestive of the complicated dynamics and sediment deposition patterns that may occur near the base of a marine terminating glacier, with a crude estimate of mean clay deposition at a rate of 6 cm per year over a distance of 2 km from the source.

中文翻译：

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通过在冰架下上升的冰羽模拟沉积物运移和沉积的实验室实验

通过观察源自海洋终止冰川底部的融水羽流携带的沉积物，进行了实验室实验，以检查从沿倾斜的上边界上升的浮线状沉淀物中沉降的颗粒的运输和沉积。如果羽流源具有较高的动量并且位于区域底部附近，则在源附近会形成一个强大的再循环区域。从该区域散发出来的是带有颗粒的浮羽，它以接近恒定的速度沿着斜坡运动。观察到颗粒沉降在羽状流本身内，然后从羽状流向罐底下降，并通过由羽状流对下层环境流体的夹带驱动的回流沿源的方向向后拉回。在源关闭且所有颗粒沉降之后，采用光衰减技术非侵入性地测量沉积物床的深度。发现沉积物在再循环区域范围内在源附近堆积，然后随着距源的距离近似线性减少。概念性理论模型表明，线性倾斜床是由于再循环区域附近羽流中的垂直混合和回流作用相结合而产生的，回流作用是更有效地从羽流源附近减少羽流颗粒，在羽流源附近，羽流和回流之间的剪切力最大。由于实验装置的限制，在许多方面，该实验不能代表稳定的冰川融水羽流，特别是相对较低的雷诺数。