الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Local scour downstream hydraulic structures may cause damage or failure of structure and loss of life and possession.This research aims to examine the effect of using semi-circular baffles on scour hole parameters downstream hydraulic structures. Different flow conditions and various geometrical parameters are considered. Results showed that the best position of the baffle is located at the first one-third of the floor length with a relative diameter equal to 0.74 to the initial water depth (gate opening). That position causes a reduction of about 50% for the maximum depth of scouring, comparing to the case of a flat floor (no baffles). On the other hand, the extended length of the scour is reduced to about 31%. On the other hand, the second position for baffles, at two-thirds of the floor length, reduces only the relative scour length to about 57% compared with the case of a flat floor without baffles.Based on the experimental results, applying the dimensional analysis technique, empirical relationships were obtained.A hundred twenty-six experimental runs were carried out under live bed scour conditions in the irrigation and hydraulic laboratory at the Faculty of Engineering, Mansoura University, Egypt.