内湾の貧酸素化防止のための潮汐ダムの開発に関する研究( 1 )

OPT及びTPT (a)の導水管導水量の推算法

抄録

The idea of the tidal dam is proposed to prevent the oxygen deficiency in the bottom layer of a themally stratified water in an enclosed bay. Ejecting the solar heated reservoir water into the sea bottom, a vertical water circulation may be generated in a highly stagnant water only by the tidal potential energy. In this study, the hydraulic feature of flows in pipes which connects the dam reservoir and the sea, is theoretically and experimentally examined to estimate the volume of total waters ejecting from the dam reservoir into the sea during one tidal cycle. Although the water flow driven by the tidal motion in this system is unsteady, the kinematic proper period of the pipe flow is considerably shorter than the tidal period. Therefore, the phenomenon which we concem here, can be practically regarded as a steady one. Neglecting the time varying inertia term in the goveming equations, the ratio of the tidal range, A in the dam reservoir to that of the sea can be represented as a function of the following parameter : where F is the energy loss coeffcient in the pipe system, ΔhB is the half of the tidal range in the sea, ω (= 2 π/T) is the angular velocity of the tidal fluctuation, T is the tidal period, g is the gravitational acceleration, SD is the area of the dam reservoir and A is the cross sectional area of a pipe. The functional relationship is verified through hydraulic model experiments.