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| Energy dissipation pattern of stepped spillways |
| Yang Jijian1, Liu Hansheng1, Zhang Feng2, Wen Mingyi1, An Mengxiong1 |
| 1.College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; 2.Hydro China Guiyang Engineering Corporation Limited, Guiyang, Guizhou 550081, China |
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Abstract Self-aerated stepped spillways are widely used for high energy dissipation ratio and less investment. In order to reflect the whole energy dissipation characteristics, and the disorder of flow,this paper introduces the concepts of relative energy dissipation ratio and relative Froude number of stepped spillways after comparing the energy dissipation ratio and Froude number of stepped spillways and corresponding smooth spillway, of which the relative energy dissipation is the difference between the stepped spillways and corresponding smooth spillway,and the relative Froude number is the difference between the smooth spillway and corresponding stepped spillways. These two hydraulic parameters reflect the ability of stepped spillways to the energy of flow and the disorder of flow, which are different from smooth spillway. Twenty-one groups of tests on stepped spillways with 26.57°, 32.01°,33.69°,38.66°and 51.3°five different chute angles, 1.43 cm-6.67 cm step heights were conducted, and the results shows the linear correlation coefficient between them is 0.9937-0.9995. The major width unit has major energy dissipation ratio with the same relative Froude number; the step height has little effect on the linear relation; and the slope has a complex effect on the linear relation, the major slope has minor Froude re-lative energy dissipation ratio when the slope is minor,however, the minor slope has minor Froude relative energy ratio when the slope is major. The law reflects the hydraulic characteristics of stepped spillway, and provides an important theory for further exploring the mechanism of energy dissipation.
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Received: 19 August 2014
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