THE INFLUENCE OF WIND AND WIND-WAVE TURBULENCE UPON TIDAL CURRENTS - TAYLOR PROBLEM IN 3 DIMENSIONS WITH WIND FORCING

A three-dimensional model of the North Sea, represented by a rectangul ar basin of constant depth, or shallowing in the south, open at its no rthern end, is used to examine the influence of enhanced turbulence an d bottom friction due to wind induced currents and wind waves upon the position of M(2) tidal amphidromes and tidal current distributions ov er the North Sea. Calculations show that enhanced levels of turbulence associated with the wind and with the wind induced currents significa ntly influence the profile of the M(2) tidal current, and also affect the higher tidal harmonics. Enhanced bed friction associated with incr eased turbulence due to wind waves can have a significant effect upon the currents, particularly in shallow water. The influence of a time v arying eddy viscosity, depending upon the magnitude of the current in coupling tidal and wind induced currents, and producing higher tidal h armonics, is examined using a single point model in the vertical. By u sing this combination of a three-dimensional model and a single point model in the vertical, the mechanisms affect the coupling of wind and tidal currents can be understood.