Dynamic aspects of estuaries | |
| Author | Le Huu Ti |
| Call Number | AIT Diss. no.D24 |
| Subject(s) | Estuaries Oscillations |
| Note | A dissertation submitted in partial fulfilment of the requirements for the degree of Doctor of Engineering. |
| Publisher | Asian Institute of Technology |
| Abstract | A study is carried out for two important dynamic aspects of well mixed estuaries: the oscillation in a harbour with a river at its back wall and the distribution of velocities due to the river flow and tidal motion in the harbour or in the open sea. Oscillation in estuary harbours. The harbours under consideration are of rectangular shape. The river is discharged from the harbour back wall, through the harbour and into the open sea. The existence of the river affects the oscillation in the harbour which is induced by waves coming from the sea. This influence is viewed from two aspects: the effect of the geometrical change due to the existence of the river and the effect of the river flow. The geometrical effect is analytically treated by extending Goda's Solution. The existence of the river generally suppresses the wave amplification factor in the harbour. The effect of inflow velocity is obtained by perturbation up to the first order. The solution obtained exhibits a change in the natural frequency as well as the amplification factor of the oscillation. Ditribution of velocities due to river flow and tidalmotion. For a better understanding of the inflow in the oscillation problem, more factors are considered in this part. A two-dimensional mathematical model is developed for this purpose. The velocities are integrated over the water depth. In the analytical approach, the neglection of convective and horizontal diffusion terms along with the assumption that bottom stresses are linearly proportional to the average velocities bring the governing equations to a simpler form. The analytical solution is then obtained for idealized estuaries, shallow and of uniform depth, which are affected by tidal motions that can be described by simple harmonic functions. This solution is improved by the method of separation of stream functions thanks to Dean's result. From these results and in reference to Kashiwamura's experimental data, discussions are made on Takano's flow pattern. This model is also expressed in terms of finite difference to solve the similar problems in nature. An application of this numerical model is carried out for Bandon Bay. In addition to the velocity distribution, the salinity distribution is included in the computation. Discuss8ions on the flow patterns are made for various possible boundary conditions at the entrance of the bay. |
| Year | 1975 |
| Type | Dissertation |
| School | AIT Publication (Year <=1978) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Dissertation (D) (Year <=1978) |
| Chairperson(s) | Nishimura, Hitoshi |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1975 |