内湾における局所的海水流動の数値計算 (第2報)

抄録

Numerical simulation of ocean current is one of significant tools which are of practical use for environmental assessment of oceanophysical effects of large floating offshore structure, for example, on the surrounding sea water. In the previous paper, the so-called multilevel model of ocean current was adopted to simulate tidal current observed in the vicinity of an existing large floating offshore structure (LFOS), called Mega-Float model, moored off Oppama, Yokosuka. As a result of comparison between the observed current and simulation results, it was concluded that the main characteristic feature of tidal current in the close vicinity of the LFOS could be reproduced satisfactorily by numerical simulation. In the present paper, variation of water temperature and salinity, in addition to current velocity, are taken into consideration in order to enable numerical simulation to reproduce more detailed features of observed tidal current. The oceanographical observation carried out at the mooring site of Mega-Float model revealed that vertical structure of tidal current at low tide was complicated and changeable : on 29th August 1995, the upper current was southward while the lower current was northward, but one day after 29th August, both currents were northward. The numerical simulation presented in this paper partly succeeded in reproducing this complicated tidal current at low tide. In addition, the effects of Mega-Float model on tidal current, sea temperature and salinity were examined using the results of numerical simulation. As a result, it was found that Mega-Float model did not bring forth untrifling difference in sea temperature and salinity.