流对波边界层湍流运动的影响

INFLUENCES OF CURRENT ON THE TURBULENT BEHAVIOUR OF WAVE BOUNDARY LAYER

采用大涡模拟方法和Smagorinsky亚格子模型,求解三维Navier-Stokes方程,研究了波流边界层中的湍流特性.将大涡模拟结果与相应的直接数值模拟结果和实验数据进行比较,吻合较好.获得了不同波雷诺数,不同波流比情况下的大涡模拟数据库,并由此分析了波流边界层中各种湍流统计量,如速度廓线、剪应力、湍流强度等的变化规律.

Turbulent flow of wave current boundary layer is numerically investigated by using Large Eddy Simulation （LES） of the Navier Stokes equations, coupled with Smagorinsky subgrid-scale （SGS） model. To validate the present calculation and verify the performance of SGS model in the LES of wave current boundary layer, the present LES results are compared with the results of direct numerical simulation （DNS）, and a reasonable agreement is found. Then, the databases of the wave current boundary layer flow are established, covering a wide range of wave Reynolds number （1000 ≤ Rew≤ 3500） and the ratio of the velocities induced by current and wave （0 ≤ uc/uw≤3.0）. The statistics, such as the velocity profiles, the Reynolds stress and the turbulence intensity, are studied. The influences of the current on these statistics are discussed. With the addition of currents, the velocity acceleration and deceleration cycle becomes asymmetrical, both the Reynolds stress and the turbulence intensity increase with the velocity of currents.