Numerical study of wind effect on green island wake

Abstract

Wind effect on Kuroshio-induced island wake downstream the Green Island, Taiwan is studied using a depth-averaged shallow-water model. Seasonal monsoon effect on spatial-temporal scales, such as aspect ratio, dimensionless width, and Strouhal number as well as propagation speed of the vortices of Reynolds number 50 is studied. It is found that northeast monsoon has more pronounced effect in wake characteristics than southwest monsoon does, in terms of flow speed and recirculation zone, the aspect ratio, and dimensionless width. Vortices are pushed back close to the island with a smaller size of recirculation when Kuroshio flows against the northeast monsoon; Vortices are pushed farther downstream with a larger size of recirculation when Kuroshio flows in favor of the southwest monsoon. However, wind effect on temporal variation of island wake seems insignificant. The Strouhal number is between 0.116 and 0.125 from numerical simulations. This value is close to result of previous reports.