| Author | Abbas, Muhammad Akhtar |
| Call Number | AIT Thesis no.WA-87-1 |
| Subject(s) | Weirs
|
| Note | A thesis study 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 | Parshall flume, standard rectangular weir, and 90° V-notch weir are
commonly used as flow measurement devices. All of them show good applicability within a limited range of discharge to be measured. However,
in a small watershed area when the rainfall is not uniformly distributed,
heavy rainfall in wet season and the low flow during the dry season, ensures considerable fluctuation of the discharges. The existing devices
are not appropriate for the flow measurement under such conditions. In
such areas, the compound weir is needed for this purpose . The necessity
of having accurate information on the performance characteristics of
compound weirs has focused attention to study its behaviour under free
overfall conditions.
A theory is outlined which helps to explain the flow over compound
weirs, whose application is shown to be reasonably justified in the
present context. Experiments on twelve weirs of three sets are shown to
confirm the trends predicted by the theory.
A discharge equation of the form Q = K.Hn is formulated, where Q is
discharge, K is dimensional constant of proportionality, H is measured
head, and n is hydraulic exponent . Such a definitive and unique relationship offers a practical basis for the measurement of discharge in
open channels. An accurate method for determining the discharge coefficients is presented and the coefficients are determined for each of the
compound weirs. The limits of validity of the results are investigated.
The summary of the results is presented in graphic and tabular forms.
Finally, sensitivity analysis, by varying the discharge coefficients
has been carried out to help identifying the potential importance of
these parameters. A comparison of the theoretically determined solution
with observations indicates a fair agreement, and allows a simple prediction of all pertinent flow characteristics. |
| Year | 1987 |
| 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) | Wang, Tsan-Wen ;Prida Thimakorn
|
| Examination Committee(s) | Bogardi, Janos J. ;Preecha Kamronrithisorn
|
| Scholarship Donor(s) | The Government of France |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1987 |