黄河口水下三角洲海底冲蚀沟发育的动力机制探讨

Study of dynamic mechanism for the formation and growth of gullylandform on the subaqueous delta near old Huanghe River mouth

根据老黄河口外水下三角洲海底冲蚀沟的地貌特征，用动力学方法分析了其形成发育机制．结果表明，波浪近底流是冲蚀沟形成发育的主导因素．冲蚀沟内的湍流及其次生的横向环流构成了复杂的流场，由此产生的边界切应力对冲蚀沟的侵蚀及沉积物的悬浮、扩散起重要作用．冲蚀沟的断面形态与流场结构密切相关．

Based on the features of gully landform on the subaqueous delta near old Huanghe River mouth, a dynamical method toanalyse mechanism for the growth of gully was used. It is shown that wave-induced near bed current is the dominant factor whichleads to growth of gully. Secondary current caused by turbulent fluctuation in the gully makes velocity field very complicated. Andboundary shear stress caused by them has an important effect on erosion of gully, and suspension and dispersion of sediment. Thepattern of gully's lateral profile is related intimatey to the velocity field of main and secondary current.