| Author | Imteaz, Md. Monzur Alam |
| Call Number | AIT Thesis no.WA-94-2 |
| Subject(s) | Waves--Mathematical models
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of
Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | This work presents linear and non-linear numerical models for computation of water level or
discharge for two layer flow in one dimensional propagation. Four governing equations, two
for each layer are derived from Euler equations of motion and continuity for two layer,
assuming long wave approximation, negligible friction and interfacial mixing. Linearized
equations for two layer are analytically solved using Fourier transform. Numerical models are
developed using staggered Leap Forg scheme. Results of linear numerical model are verified
by comparing with analytical solution for different boundary conditions. Good agreement
between analytical and linear numerical model is observed for most of the boundary cases.
Stability condition is discussed and found that CFL stability condition( considering interface
wave celerity as physical celerity) is not directly applicable. A modified stability condition, M
~ Lix( 1/Max{c1, c2} - 1/300 ) is suggested. Adding non-linear terms non-linear numerical
model is developed and compared with linear numerical model for different 11/h. Significance
of non-linear terms are discussed. Non-linear numerical model is used for the cases of
progressive internal wave in to the incline bay and oscillation in the lake due to the presence
of two layer non-uniform depths. For the first case it is found that effect of adverse bottom
slope towards the direction of wave propagation is to amplify the wave and this amplification
depends on the steepness of slope as well as the ratio of densities of upper layer fluid to lower
layer fluid (a). For steeper slope amplification is higher and for higher 'a' value amplification
of top surface and interface decreases which are reasonable. For the case of oscillation in the
lake it is found that results depend on the value of 'a' and if 'a' increases, the magnitude and
rate of oscillation of both the top surface and interface decreases which is also reasonable. The
model can be applied confidently to simulate the basic features of different practical problem
similar to that investigated in this study. |
| Year | 1994 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Imamura, Fumihiko
|
| Examination Committee(s) | Tawatchai Tingsanchali ;Sutat Weesakul |
| Scholarship Donor(s) | NORAD. |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1994 |