Analysis on Mechanism of Mixing and Turbulent Diffusion in Tidal River Estuary

本计画之研究成果包括日治感潮河川实测资料、三层流模式之实际验证及潮汐异重流之数值模拟.现场观测：利用双元电磁传感器系统在日治河口进行了河口潮汐观测。用其他系统（螺旋桨仪、电导率仪、水温仪）对盐跃层附近的测量范围进行了初步探索。由模拟量到离散量的排列是在16<beta>位微机系统的支持下，通过A/D转换器和可选的数字转换器实现的.实际验证：首先，时间平均流速和盐度的平均值测量obsatined。与此相对应，对湍流脉动u 'u'、w 'w'、u 'w'、混合长度和涡动粘性进行了详细的分析。并利用这些物理量对三层流模型进行了验证。第二，分别用岩崎数和理查森数的幂函数表示界面间相互作用力的数值计算.数值模拟：采用有限差分法模拟了垂直面内的二维异重流。

The results of this project are composed of field measurements in Hiji Tidal river, practical verification for Three-layered Flow Modal and Numerical simulation of tidal density flow.1. Field Observation; Tidal estuary observations were carried out by the electromagnetic sensor system with two-elements in Hiji river estuary. The range of measurement arround halocline were searched by the other system(propeller meter, electric conductivity and water temterature) simultaneausly. The arrangement from analogous to discrete quantity were coducted by 16<beta>-personal computer system supported by A/D-converter and optional amplifier.2. Practical Verification; First, time-averaged velocity and salinity were obsatined from the mean values measurements. Corresponding these results, the detailed analysis of turbulent fluctuations which were u'u', w'w', u'w',mixing length and eddy viscosity were fulfilled. And then, Three-layered flow model were verified with these physical quantities successfully. Second, numerical evaluation of mutual entrainments across the interfaces were represented by a power function with respect to Iwasaki number or Richardson number respectively.3. Numerical Simulation; Two-dimensional density flow in vertical plane were simulated by F.D.M.