The Experimental Study On Flow Characteristics Of Tetrahedron-like Penetrating Frame And Bank-protection Application

As a new technique for flood prevention and bank-protection, the tetrahedron-like penetrating frames actualize its function by changing velocity distribution. At present, the tetrahedron-like penetrating frames are applied successfully to projects, and some investigation results of this technology are attained. However, the designs and constructions of the tetrahedron-like penetrating frames in project are always made according to experience, and there are short of guidance of systemic theory. Based on the results of present investigation, the research for flow characteristic and resistance characteristic of the tetrahedron-like penetrating frames is carried out by theoretic analysis and physical model experimentation. And combining with the water-sediment characteristics, reasonable layout of bank-protection of tetrahedron-like penetrating frames are studied. The main contents of this paper are as follows:(1) Through theoretic analysis, the study on mechanism of the tetrahedron-like penetrating frames is carried out from various aspects, such as velocity of flow, resistance, energy transformation and turbulent shear stress.(2) Through flume experiments, the flow characteristics of the tetrahedron-like penetrating frame is compared with tetrahedron-like solid block, and the deceleration characteristics of different composite forms of tetrahedron-like penetrating frame are studied.(3) Resistance characteristics of the tetrahedron-like penetrating frames are carried out by experiments, and the influence of frame quantity (density) and water depth on resistance is studied. Then, the mechanism of bank-protection of the tetrahedron-like penetrating frames is discussed by combining the test results with theoretics analysis.(4) Based on the water-sediment characteristics of Nanjing stage of Yangtse River, reasonable layouts of the tetrahedron-like penetrating frames for flood prevention and bank-protection are investigated. Drop-distance in the frame dumping is discussed. The results can be used for reference to the design of bank-protection works.