Experimental Investigation on the Characteristic of Air Entrainment on the Stepped Spillways
Zhang Zhichang,Zeng Dongyang,Liu Yafei
(Xi'ang Unviersity of Technology, Xi'an Shaanxi, 710048)

Abstract: The air entrainment is the key point of the air erode and the security of the operation on the stepped spillways. The phenomenon and the division method of air entrainment on the stepped spillways have been studied by experimental mthod. The along-road air entrainment on the stepped spillways can be divided into 3 regions which are the non-entrainment region, the development region and the air sufficient region. The sectional air entrainment can be divided into 4 regions which are the bottom air entrainment zone, cuniform pure water zone, bubble zone and drip zone. The along-road distribution of the sectional air entrainment thickness has also been studied in the experiment. The sectional water containing index has been calculated. The calculating method of the initial air entrainment point on the stepped spillways has been declared. Compared with that of the slippery spillways, the initial air entrainment point of the stepped spillways moves forward. The air entrainment of the stepped spillways occur earlier, develope quickly. And the thickness of air entrainment is large.
Keywords: stepped spillways, the air entrainment characteristic, the initial air entrainment point.