03568nam a2200397 4500 20260818223013.0 030698 th eng .b10649979 AIT Thesis no.WA-87-1 Abbas, Muhammad Akhtar A study of compound weirs Bangkok : Asian Institute of Technology, 1987 135 p. Thesis ; no. WA-87-1 A thesis study submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology Thesis (M.Eng.) - Asian Institute of Technology, 1987 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. Weirs Wang, Tsan-Wen, Chairperson Prida Thimakorn, Co-Chairperson Bogardi, Janos J., Examination Committee Preecha Kamronrithisorn, Examination Committee The Government of France, Scholarship Donor Asian Institute of Technology. Thesis ; no. WA-87-1 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B19395 .b10649979 mnait s 240401 2 951012 m a s 2 mnait mnarc 22 40 Barcode : 30050120573604 CREATED : 2014-01-04 RECORD # : i12785106 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050160034814 CREATED : 2016-09-02 RECORD # : i12879277 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 114525 114525 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.WA-87-1 30050120573604 2026-08-18 22:30:13 3 2026-08-18 22 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.WA-87-1 30050160034814 2026-08-18 22:30:13 2026-08-18 40