部分冰盖下水流水力特性数值模拟

运用Fluent软件建立雷诺应力模型，模拟不同冰盖覆盖度下恒定均匀流流场，从纵向时均流速、二次流、雷诺应力、紊动能等方面揭示部分冰盖下水流的水力特性。结果表明：岸冰的形成会导致冰盖下水流在断面上重新分配，明流区流速增大，冰盖下流速减小；横向动量交换产生复杂的二次流结构，涡体形状、数量、大小和位置随着冰盖覆盖度的增加而变化；雷诺应力断面分布较复杂，冰盖附近区域雷诺应力为负值，负值区范围与冰盖覆盖度密切相关，并凸向明流区；冰盖、边壁和床面的粗糙度不同导致紊动能在断面上的分布呈现出明显的差异，冰盖区紊动能大于明流区的值，反映出岸冰对冰盖下水流结构影响的复杂性。

Numerical simulation on hydraulic characteristics of steady flow in channels with partial ice cover

The Fluent-based Reynolds stress model was applied to simulate the hydraulic characteristics of steady uniform flow in channels with partial ice cover in terms of streamwise velocity, secondary flow, Reynolds stress, and turbulent kinetic energy. The simulated results show that the formation of border ice results in the redistribution of under-ice flow on the cross section, the velocity increases in the open-water subsection, but decreases in the under-ice subsection. The resulting lateral momentum transfer produces a complex secondary flow structure, the shape, number, size and location of the vortices vary with the coverage of ice cover. The distribution of Reynolds stress is complex with negative value in the near-cover region of the under-ice subsection, and the negative region is closely related to the ice coverage, which forms a convex shape towards the open-water subsection. The differences in the roughness of ice cover, bed and side-wall result in the variation of turbulent kinetic energy in the cross section. The turbulent kinetic energy is larger in the under-ice subsection than that in the open-water subsection, indicating that the formation of border ice has complicated effects on the turbulence structure of the under-ice flow.