内湾の物質分散過程における潮流と恒流の相乗効果

Abstract

It is well known that the strong tidal current at the narrow strait of the inner bay forms thetypical constant-flow vortices. To clarify the water exchange through such a strait, the couplingeffect of the constant flow and the tidal oscillatory flow is examined. It is shown that the couplingeffect yields the 8-shaped Lagrangean motion through which adjacent vortices intercommunicate, inducing water exchange between them. The exchange coefficient is large enough that it reachesthe values usually reported in field observations. The motion diffuses the sea water substantiallyin time scale longer than the tidal period. The exchange coefficient and the dispersion coefficientare both proportional to the square of the magnitude of the constant flow.