| Author | Amaraporn Sriram |
| Call Number | AIT Thesis no. WA-92-30 |
| Subject(s) | Channels (Hydraulic engineering)
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of
Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Experimental studies were conducted in a rectangular tilting flume. A half symmetrical
rectangular compound section was used in this study. Twelve cross-sectional configurations were ยท
used to investigate the effect of cross-section geometry on C-y curve given by Chaudhry and
Bhallamudi (1988). The bed slope was varied from steep slope to mild slope or vice versa when the
discharge is constant for each experimental run. The discharge was varied at least 7 times for each
cross-sectional configuration in order to verify the method of determining critical depth in compound
channel previously derived by Chaudhry and Bhallamudi.
The water depth was measured by point gauges and the discharge was measured by using the
90 degree V-notch weir at the downstream end of flume. The mean flow velocity was calculated
from the discharge divided by the total area. The specific energy and Froude number equations were
used for data analysis .
. The experimental results obtained from this study indicate that there are three cases of flow
in the compound channel. Firstly, there is only one critical flow occurs only when the flow is in the
main channel. Secondly, three critical depth occur. One _critical depth occurs when the flow is in
the main channel and the others occur when the flow is over bank. And thirdly, there is only one
critical depth occurs when the flow is over bank.
The critical depths for various of discharges and cross-sectional configurations were obtained
graphically from the relationship between the Froude number and water depth (Fc-Y curves) at the
point which is Fe equal to 1. The results show that the depths at local minimum and maximum
specific energy of the specific energy and depth (E-Y) curve may not be the critical depth for the
channel which have compound cross-sections because at this point ,Froude number is not equal to
1. The C-y curves from experimental results were plotted in the same graph with the analytical
results according to the equations derived by Chaudhry and Bhallamudi. It was found that the method
given by Chaudhry and Bhallamudi is give very good agreement with the experimental results based
on the Fc-Y curves. It is verified that their method is applicable for the channel with have symmetrical
cross-section. The effect of geometry of compound cross-section was observed that it has significant
influence on C-y curve. The value of Cmax on the C-y curve is directly proportional to the ratio of
the berm width and the main channel width brand the error in C-y curve of the experimental results
from the E-Y curve is decreases when br decreases. The effect of the interaction between main
channel and floodplain was observed that it can be neglected for the compound section which the
roughness coefficient of the main channel and floodplain is not much different. |
| Year | 1992 |
| 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) | Tawatchai Tingsanchali |
| Examination Committee(s) | Loof, Rainer ;Tran Thuc
|
| Scholarship Donor(s) | German Academic Exchange Service (DAAD) |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1992 |