Characteristics of the Hydraulic Jump in Trapezoidal Channel Section

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Water Recourses Engineering Department, College of Engineering, Al-Mustansiryia University, Bab AL- Muthem, P.O. 14150, Baghdad, Iraq.

Abstract

In this study, characteristics of the hydraulic jump in trapezoidal channel sections were analyzed and a general equation represents the solution of the hydraulic jump in the channels of arbitrary cross-sections (rectangular, triangular & trapezoidal) was driven depending on the momentum principle. The solution of the models was provided using Newton Raphson method. Consequently, Tables and charts of family curves of the conjugate depths ratio (r=y2/y1) have been prepared, for a very wide range values of Froude numbers and section ratios (k=b/zy). For each type of cross sections, the efficiency of the energy dissipation of the hydraulic jump was also analyzed and compared with each others. The relationship between the initial and sequent Froude numbers (FD1 and FD2) has been indicated for various values of k1=b/zy1. Depending on the results of conjugate depths ratio r = y2 / y1, the length of the hydraulic jump were estimated for a very wide range of k1=b/zy1, using two suggested models. It was found that the channel shape has insignificant effect on the efficiency of the energy dissipation of the hydraulic jump, although the triangular section tends to be more efficient than the others by about 10 percent in higher FD1. When (FD1 > 6), the velocity head after the jump could be neglected. When the section ratio k1 is approximately 3, the length ratio of the hydraulic jump (Lj / y2) reaches to a maximum value independent on the value of FD1. In all cases, it was shown that the comparison of the theoretical results with other experimental data indicate a very good agreement

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Journal of Environmental Studies
Volume 9, Issue 1
December 2012
Pages 53-63

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