INFLUENCES OF CURRENT ON THE TURBULENT BEHAVIOUR OF WAVE BOUNDARY LAYER

Turbulent flow of wave current boundary layer isnumerically investigated by using Large Eddy Simulation (LES) of the Navier Stokesequations, coupled with Smagorinsky subgrid-scale (SGS) model. To validatethe present calculation and verify the performance of SGS model in the LESof wave current boundary layer, the present LES results are compared withthe results of direct numerical simulation (DNS), and areasonable agreement is found. Then, the databases of the wavecurrent boundary layer flow are established, covering a wide range of waveReynolds number (1000 \le Re_w \le 3500) and the ratio of the velocitiesinduced by current and wave (0 \le u_c / u_w \le 3.0). The statistics,such as the velocity profiles, the Reynolds stress and the turbulenceintensity, are studied. The influences of thecurrent on these statistics are discussed. With the addition of currents,the velocity acceleration and deceleration cycle becomes asymmetrical, boththe Reynolds stress and the turbulence intensity increase with the velocityof currents.