| Author | Hossain, K. M. Anwar |
| Call Number | AIT Thesis no. WA-89-04 |
| Subject(s) | Hydraulics
|
| Note | A thesis submitted in partial fulfilment of the requirements
for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Most of the natural channels have permeable beds of sand,
gravel and boulder. The interaction between flow and permeable
boundary modifies the flow characteristics, such as velocity
profile, resistance to flow. The aim of present study is to
investigate the characteristics of flow over permeable bed, in
particular, the velocity profile and bed resistance.
Velocity distribution over permeable bed in a smooth
rectangular channel was studied experimentally. Two sets of
experiments were performed in a slope adjustable tilting flume:
one with 8 cm thick and other with 10 cm thick of uniform gravel.
Measurements were conducted with five different bed slopes, each
comprising of seven different discharges for a particular gravel
size. Velocity distributions were measured by micro propeller
current meter along the depth at an interval of 0.5 cm.
Velocity distribution above the permeable bed can be
represented by composite curve of logarithmic and parabolic
distribution for specified depths. The outer and central zones
conform to logarithmic and parabolic laws respectively with datum
as the normal bed surf ace while the inner zone follows
logarithmic law by considering the reference datum shifted below
the nominal bed surface. From the analysis of boundary resistance
in the main channel flow it is observed that the friction factor
increases with the increase of Reynolds number. For a given
Reynolds number the friction factor decreases with the increase
of relative roughness. The value of friction factor, f, Manning's
n and Chezy's C computed from composite and logarithmic velocity
profile throughout the depth of flow are not differed
significantly. Computed friction factors are found to be within
the range of +5% deviation from observed friction factor. |
| Year | 1989 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Gupta, Ashim Das;Paudyal, Guna N.; |
| Examination Committee(s) | Akiyama, Juichiro; |
| Scholarship Donor(s) | DAAD;FRG; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1989 |