VARIATIONS OF REYNOLDS STRESS DEPENDING ON COORDINATE AXIS IN WAVE-CURRENT COEXISTING FIELDS

Abstract

 Horizontal coordinate axis in a wave-current coexisting field like an inner bay is important in order to estimate Reynolds stress. Therefore, effects of coordinate axis on Reynolds stress depending on the directions of waves, mean flow and tidal current were investigated by a coordinate transformation of simultaneous horizontal velocities and eliminating wind wave components through a spectrum analysis. As the result of this study, it is made clear that an absolute value of Reynolds stress has to be small by a coordinate transformation to a wave direction in cases wind waves are dominant, and that to a mean or a tidal flow direction in cases wind waves are small. In addition, the approximate value of a dimensionless parameter to estimate the necessity to eliminate wind wave components from Reynolds stress was obtained. Therefore, detailed flow conditions would be understood by an appropriate horizontal coordinate axis in consideration with dominant directions of wind waves, mean flow and tidal current.