| Author | Dey, Ashis Kumar |
| Call Number | AIT Thesis no.WM-97-15 |
| Subject(s) | Flood routing--Mathematical models
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. WM-97-15 |
| Abstract | Two types of flood flow models have been developed. The first one is the one
dimensional flood flow model which is applied to simulate flood flow condition along the
main channel of river Ganges, Bangladesh. The second one is the two dimensional flood flow
model for simulating the propagation of flood wave through the main channel, berm and its
offstream flood plain. The superiority of two dimensional model over the one dimensional
has been studied.
The one dimensional model has been developed based on finite difference implicit
scheme in which the basic equations are the continuity and momentum of Saint Venant type.
The two dimensional model has been developed based on alternative direction implicit (ADI)
scheme utilizing the continuity, X- and Y- momentum equations. The models have been
calibrated and verified with the field data successfully. Effects of the model parameters such
as roughness coefficient, weighting factor, time and space increment etc. on the computed
results also have been m(l.de carefully.
In one dimensional model, it has been observed that the Manning's n has a significant
effect on the computed discharges and velocities but no effect on the computed water level.
Two dimensional model shows that the weighting factor of the effective stresses (a), friction
factor of main channel (fc), friction factor of berm (fb) and the time increment (Δt) have a
significant effect on the computed results. Higher values of friction factors decrease the
velocities both in the main channel and berm. Smaller value of a increases the longitudinal
velocities in the main channel but decreases the same in the berm. The higher value of a in
the berm than that of the main channel increases the lateral momentum transfer across the
transverse section.
Two dimensional model provides the better accuracy in computations than the one
dimensional and it gives the results both for main channel and berm simultaneously. One
dimensional model gives the most accurate results for the value of Manning's n equal to
0.015 while the most accurate results from two dimensional model are obtained for fc equal
to 0.00045, fb equal to 0.0164 and a equal to 0.50. Good agreement between the computed
results and observed data implies that the models are capable to simulate the flood flow accurately. |
| Year | 1998 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. WM-97-15 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Tawatchai Tingsanchali ; |
| Examination Committee(s) | Kubo, Naritaka;Kazama, So; |
| Scholarship Donor(s) | Danish International Development Agency; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |