断面曲率半径对海底浊流的影响

基于雷诺平均的纳维尔-斯托克斯模型,三维数值模拟研究海底浊流在断面顶宽相同、但曲率半径不同的2个圆弧形弯曲渠道内的流动及沉积。结果表明:断面曲率半径大、边坡平缓渠道内的浊流更易在弯道顶点及其下游处发生溢流,而断面曲率半径小、边坡较陡的渠道浊流更易对边坡形成侵蚀,使浊流在渠道内流至下游时依然保持较高的流速及强度;经多次浊流事件的侵蚀及沉积,圆弧形的渠道渐渐向不对称的梯形转换;提高流向坡度会改变弯道顶点中心处二次流的方向。

Influences of Cross-sectional Curvature on Turbidity Currents in Sinuous Submarine Canyons

A three-dimensional computational model based on Reynolds-averaged Navier-Stokes equation was used to study the flow and deposition of turbidity currents in two sinuous submarine canyons with the same cross-sectional top width but different curvature. The important findings are： for sinuous channel with higher cross-sectional curvature, turbidity current within the channel are more likely to spill over the bank of the channel bend apex and its downstream, while for channel with lower cross-sectional curvature, erosion occurs more easily and thus maintains relatively strong current downstream; channels with arc cross section gradually transform to asymmetric trapezoidal shape after erosion and deposition of multiple events of turbidity currents; increasing downstream slope may change the direction of bed secondary flow at the center of sinuous channel bend apex.