الفهرس | Only 14 pages are availabe for public view |
Abstract DROP structures, due to simplicity of building and maintenance, are one of the most common and important hydraulic structures used for dissipating the excess energy and water transmission from a higher level to a lower level as well. The excess energy of flow is dissipated in two mainly different ways; one due to the geometric shape of the drop, which occurs along the structure and the other due to hydraulic jump which forms downstream spillway. If the effective parameters on DROP structure would be better recognized, it would be possible to minimize the dimensions of the DROP and further supplementary structures such as stilling basin. Two hundred and ninety night experimental runs were carried out in the Hydraulics and Water Engineering Laboratory of the Faculty of Engineering, Zagazig University. Seven stepped spillway models with inclination face angle equal 29.05, fixed height and fixed length but with different steps dimensions. Different types of breakers on the steps of the spillway, and breakers on the steps with cylindrical baffles on the basin of spillway were tested under different flow conditions. It was found that, all suggested arrangements of breakers and breakers with baffles caused a noticeable reduction loss of energy. It was noticed that, the stepped spillway with four steps gives the maximum energy losses than other stepped spillways. The case of fully breakers with height equal to 0.8 the height of steps with 3 holes having an area equal 5% of breakers area was found to be the best breaker than another breakers. The case of fully breakers with height equal to 0.8 the height of steps with 3 holes which area equal 5%. Moreover ,plus by putting straight fully baffles with diameter equal 60 mm gives over stilling basin were found to be more efficient for dissipating energy compared to the other different diameters baffles or different shapes of baffle. |