{"title":"Velocity Distribution in Open Channels: Combination of Log-law and Parabolic-law","authors":"Snehasis Kundu, Koeli Ghoshal","volume":68,"journal":"International Journal of Mathematical and Computational Sciences","pagesStart":1234,"pagesEnd":1242,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/10537","abstract":"
In this paper, based on flume experimental data, the velocity distribution in open channel flows is re-investigated. From the analysis, it is proposed that the wake layer in outer region may be divided into two regions, the relatively weak outer region and the relatively strong outer region. Combining the log law for inner region and the parabolic law for relatively strong outer region, an explicit equation for mean velocity distribution of steady and uniform turbulent flow through straight open channels is proposed and verified with the experimental data. It is found that the sediment concentration has significant effect on velocity distribution in the relatively weak outer region.<\/p>\r\n","references":"[1] D. Coles, \"The law of the wake in turbulent boundary layer,\" Journal of Fluid Mechanics, vol. 1, pp. 191-226, 1956.\r\n[2] I. Nezu, and W. Rodi, \"Experimental study on secondary currents in\r\nopen channel flow,\" Proceedings of the 21st IAHR Congress, pp. 115-\r\n119, Melbourne: IAHR, 1985.\r\n[3] I. Nezu, and H. Nakagawa, \"Turbulence in open-channel flows,\" Balkema, Rotterdam NL., 1993.\r\n[4] S. Vedula, and A. R. Rao, \"Bed Shear from Velocity Profiles: A NewApproach,\" Journal Hydraulic Engineering, vol. 111, no. 1, pp. 131-143,1985.\r\n[5] V. A. Vanoni, \"Velocity Distribution in Open Channels,\" Civil Engineering,\r\nASCE, vol. 11, no. 6, pp. 356-357, 1941.\r\n[6] J. B. Francis, \"On the cause of the maximum velocity of water flowing in\r\nopen channels being below the surface,\" Trans. ASCE, vol. 7(1), no. 1,\r\npp. 109-113, 1878.\r\n[7] F. P. Stearns, \"On the current meter, together with a reason why the\r\nmaximum velocity of water flowing in open channel is below the surface,\"\r\nTrans. ASCE, vol. 7, pp. 331-338, 1883.\r\n[8] J. O. Hinze, \"Turbulence,\" McGraw-Hill, New York, 1975, pp. 698-699.\r\n[9] G. H. Keulegan, \"Laws of turbulent flow in open channels,\" J. Res., Nat.\r\nBureau of Standards, vol. 21, pp. 707-741, 1938.\r\n[10] K. V. N. Sarma, B. V. R. Prasad, and A. K. Sarma, \"Detailed Study\r\nof Binary Law for Open Channels,\" Journal Hydraulic Engineering,\r\nvol. 126, no. 3, pp. 210-214, 2000.\r\n[11] V. A. Vanoni, \u201cTransportation of suspended sediment by water,\u201d Transaction of ASCE, vol. 111, pp. 67-133, 1946.\r\n[12] H. A. Einstein, and N. Chien, \u201cEffects of heavy sediment concentration\r\nnear the bed on velocity and sediment distribution,\u201d U. S. Army Corps\r\nof Engineers, Missouri River Division Rep. No.8, 1955.\r\n[13] V. A. Vanoni, and G. N. Nomicos, \u201cResistance properties in sedimentladen\r\nstreams,\u201d Trans., ASCE, vol. 125, pp. 1140-1175, 1960.\r\n[14] C. Elata, and A. T. Ippen, \u201cThe dynamics of open channel flow with\r\nsuspensions of neutrally buoyant particles,\u201d Technical Report No.45, Hydrodynamics Lab, MIT. 1961.\r\n[15] N. L. Coleman, \u201cEffects of suspended sediment on the open-channel\r\nvelocity distribution,\u201d Water Resources Research, vol. 22, no. 10,\r\npp. 1377-1384, 1986.\r\n[16] G. Parker, and N. L. Coleman, \u201cSimple model of sediment-laden flows,\u201d\r\nJournal of Hydraulic Engineering, ASCE, vol. 112, no. 5, pp. 356-375,\r\n1986.\r\n[17] F. Cioffi, and F. Gallerano, \u201cVelocity and concentration profiles of\r\nsolid particles in a channel with movable and erodible bed,\u201d Journal\r\nof Hydraulic Engineering, ASCE,, vol. 129, no. 3, pp. 387-401, 1991.\r\n[18] J. Guo, \u201cTurbulent velocity profiles in clear water and sediment-laden\r\nflows,\u201d Ph.D. dissertation, Colorado State University, Fort Collins, CO\r\n1998.\r\n[19] X. Wang, and N. Qian, \u201cTurbulence Characteristics of Sediment-Laden\r\nFlow,\u201d Journal Hydraulic Engineering, vol. 115, no. 6, pp. 781-800,\r\n1989.\r\n[20] S. Q. Yang, S. K. Tan, and S. Y. Lim, \u201cVelocity Distribution and\r\nDip-Phenomenon in Smooth Uniform Open Channel Flows,\u201d Journal\r\nHydraulic Engineering, vol. 130, no. 12, pp. 1179-1186, December\r\n2004.\r\n[21] X. Wang, Z. Y. Wang, M. Yu, and D. Li, \u201cVelocity profile of sediment\r\nsuspensions and comparison of log-law and wake-law,\u201d Journal Hydraulic\r\nResearch, vol. 39, no. 2, pp. 211-217, 2001.\r\n[22] J. Guo, and P. Y. Julien, \u201cTurbulent velocity profiles in sediment-laden\r\nflows,\u201d Journal Hydraulic Research, vol. 39, no. 1, pp. 11-23, 2001.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 68, 2012"}