An Analysis of changes in hydraulic parameters on water entrainment in converging channels

Journal of Water Science & Engineering

مقاله 6، دوره 1، شماره 3، خرداد 2012، صفحه 73-88   

نوع مقاله: Original Article

نویسندگان

A Moradi^* ؛ M Ghomeshi؛ B sarvarinezhad

Department of Water Structures, shahid Chamran University, Ahwaz.

چکیده

Building of Dam from thousands of years BC was known, and the humans with use of them always
try to preserve and utilize surface water resources, but sedimentation problem always is the most
important factor in shortening the useful life of dams , and a lot of reservoirs were filled by sediments
due to this process and therefore most of dams have been abandoned. One of the most important
phenomena that affects sedimentation is density current. Research must be continue to recognize the
role of this phenomena in sediment process. In this research the effect of changes in parameters such
discharges, concentration and slope gradient in density currents were investigated in the converging
channels. Experiments were carried out in a flume with changeable bed slope, width 72.5 cm, depth 60
cm, Length 6 meter, three convergence angle, three discharge, three concentrations and three bed slope
in laboratory models of hydraulic of Shahid Chamran University. The results showed that increase of
discharges and slope gradient will increase water entrainment and increasing of concentration will
decrease it. Finally an equation is presented for water entrainment in each convergent angle.

کلیدواژه‌ها

water entrainment density currents converging channels sedimentaion dams reservoir

مراجع

- مرکز تحقیقات منابع آب ایران.( 2002). اندازه‌گیری پدیده جریانات غلیظ در مخزن سد سازمان آب و برق خوزستان.

-Dallimoree, C. Imberger J and Ishikawa T. (2001). Entrainment and turbulence in a saline underflow in lake Okagava.  J. of  Hydr. Engin, ASCE, 127(11), 937-948.

-Ellison T.H., Turner J.S.( 1959). Turbulent entrainment in stratified flow. Journal of Fluid Mechanics, Vol.6, No. 3,pp. 423 – 448.

-Garcia M.H., Parker G.( 1993). Experiments on the entrainment of sediment into suspension by a dense bottom current. Journal of Geophysical Research, Vol. 98, No. C3, pp. 4793-4807.

-Haghiabi, A.H. (2004). The study of bed slope effect on velocity and concentration profiles of density currents. Ph.D Thesis, Shahid Chamran University, Ahwaz, Iran.