TIDAL FLOW SIMULATION FOR THE EFFECT OF SEABED CONFIGURATION ON EXCHANGE RATE OF SEA WAFER IN OMURA BAY

Abstract

Omura Bay in Nagasaki Prefecture, which is almost isolated from the outer sea, is famous for the very low exchange rate of sea water. In the present paper, the authors carry out the tidal flow simulation using the simulation system improved with the automatic control method, and it is discussed that the effect of seabed configuration on the exchange rate of sea water in Omura Bay. At first, it was estimated that the current rate ranges from 0.2 to 0.4%. Secondly, the authors performed the simulation tests with the modified seabed configuration which is cut the sea mount and buried the deep basin, respectively or simultaneously. It was confirmed that there are little changes of tide, the averaged rates become higher than current one and the water mass pattern nearby the bay mouth stretches into the depths of the bay.