On the Total Flow Control Equations and Characteristics of Unsteady Gradually Varied Flow in Open Channels
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Most unsteady channel flows in nature and practical engineering appear as gradually varied wherein the free surface deformation conforms to the long wave hypothesis. Currently one-dimensional total flow models are used to conduct numerical simulation of long-term and long-distance reaches to describe water movements, however, the models are insufficient to connect descriptions of flow field and total flow. Moreover, few studies of the variations of roughness coefficient change with time in unsteady flows have been conducted. The following results were obtained through theoretical analysis and numerical simulations in this paper. (1) One-dimensional total flow control equations of unsteady gradually varied flow in open channels were obtained directly from the mathematical model of viscous fluid motion, and can both reflect the influence of turbulence and provide an explicit expression of the energy slope item. These equations establish a direct connection between the descriptions of three-dimensional flow fields and one-dimensional total flows. (2) Synchronous prototype observation data and planar two-dimensional numerical simulation results were used to extract the one-dimensional total flow information and discuss the total flow characteristics. (3)The magnitude orders of items in the total flow motion equation were compared, and the change of the roughness coefficient with time was analyzed.
Key wordsOpen channel unsteady flow total flow characteristics control equations
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- Graf W. H., Altinakar M. S. Hydraulique fluviale [M]. University of Electronic Science and Technology of China Press, 1997.Google Scholar
- Henderson F. M. Open Channel Flow [M]. New York, USA: Macmillan Comp, 1966.Google Scholar
- Akan A. O. Open Channel Hydraulics [M]. Amsterdam, USA: Butterworth–Heinemann, 2006.Google Scholar
- Nezu I., Sanjou M. PIV and PTV measurements in hydro–sciences with focus on turbulent open–channel flows [J]. Journal of Hydro–environment Research, 2011, 5(4): 215–230.Google Scholar
- Hirt C. W., Nichols B. D. Volume of fluid (VOF) method for the dynamics of free boundaries [J]. Journal of Computational Physics, 1981, (39): 201–225.Google Scholar
- Xibing Zhang, Ruilan Yin. Planar 2–D flow and sediment mathematical modeling [J]. Advances in water science, 2002, 13(6):665–669 (in Chinese).Google Scholar
- Zhou X. L., Liu J., Luo Q. S. et al. Further research of 1D numerical simulation of unsteady channel flow [J]. Engineering Journal of Wuhan University, 2010, (8): 443–445(in Chinese).Google Scholar