| Author | Khan, Md. Sayedur Rahman |
| Call Number | AIT Thesis no.WA-90-17 |
| Subject(s) | Sediment transport
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | MIKE 11 Sediment Transport and Morphological (ST) model is a one dimensional movable boundary numerical model which simulates the change of sediment transport rate, channel roughness, channel bed, bed form dimensions etc. The model is a recent addition to the MIKE 11 system. It runs in parallel to the Hydrodynamic (HD) model of the system. The computed bed and water surface profiles, local sediment transport rates, erosion of deposition, roughness coefficients etc. by the model were compared with the observed results obtained from the experiments in a laboratory flume. Both steady uniform and non uniform flow experiments were carried out with different flow and sediment transport boundary conditions under bed load transport. Eight steady inform flow experiments were carried out to compare the sediment transport rate with that calculated from the model. Four Steady non uniform flow runs with initial triangular sand dune, initial triangular depression in bed and channel constriction were carried out to compare the transient bed profiles with the model results.
The ST model was executed with the same geometry and boundary conditions of each experimental run. The Model computes the sediment transport rate using three sediment transport furmulae namely: Engelund and Hansen, Ackers & White and Engelund & Fredosoe. It was found that in uniform flow, the sediment load predicted by the Ackers & White and the Engelund & Fredsoe formula was close to the observed results while the Engelund & Hansen formula over estimates the observed results. The bed form dimensions calculated by the Engelund & Fredsoe formula under estimates the observed bed form dimensions. The overall matching of the computed and observed bed profiles in non uniform flow are satisfactory with the Ackers & White formula.
A Sensitivity analysis was done to check the model sensitivity to different parameters such as effects of Manning's number, M. sediment inflow, grain size of sand, transport formulae etc. It was found that the model in highly sensitive to the grain size of the sediment. The other parameters have insignificant effects on the sediment transport and bed level calculation. Finally, it was concluded that the model can be used with sufficient accuracy to simulate the transient bed profiles in a laboratory flume under a non uniform flow using the calibrated transport formulae. |
| Year | 1990 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Jensen, Niels Einar ;Tawatchai Tingsanchali
|
| Examination Committee(s) | Akiyama, Juichiro ;Loof, Rainer
|
| Scholarship Donor(s) | The Government of Switzerland |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |