Author(s): Yongheng Zu; Peng Lu; Yuanren Xiu; Xuhao Gang; Yukui Tian; Qiaosheng Zhao
Linked Author(s):
Keywords: Internal waves; Ridged model ice; Froude number; Form drag coefficient
Abstract: Internal waves can be generated at the pycnocline in summer Arctic condition, affecting the momentum exchange between sea ice and ocean. In this study, both laboratory experiments and numerical simulation have been performed based on a two-layer fluid approach to better understand the effect of internal waves on keel form drag. A critical Froude number, Fr0 ≈ 1, divided the variation of the form drag coefficient into two parts: a) subcritical flow, where major nonlinear variation occurred in form drag coefficient, and b) supercritical flow, where form drag coefficient tended to a stable value with changing hydraulic conditions. According to the results of numerical simulation in deep water, a parameterization scheme of form drag coefficient has been developed with three parameters, Froude number, the ratio of keel depth to pycnocline depth, and keel slope angle. Form drag coefficient depended on Froude number in a nonlinear manner. For a moderate keel depth, Form drag coefficient increased to a maximum which is 3 or 4 times as much as the coefficient in a homogeneous fluid.
Year: 2024