利根川感潮域における塩水流動の現地観測および数値シミュレーション

抄録

Dynamic motion of salt wedge was investigated in the Tone River estuary by field experiment and numerical flow simulation. In the field experiment, vertical profiles of salinity and velocity were measured from a boat pursuing the head of salt wedge along the deepest line of the channel. Being based on the collected data, characteristics of the velocity and the structure of the salt wedge front under transitional condition of flow rate and tide were discussed. Numerical flow simulation by using a vertical 2-D k-ε model reproduced the major characteristics of the motion of salt wedge obtained from the field measurement quantitatively: (a) dependency of the distance of salt wedge invasion on tide amplitude, (b) a time lag of the salt wedge motion behind the tide oscillation, and (c) asymmetric tendency of the motion of salt wedge at ebb tide and the flood tide.