Keywords
shear plate
fixed and mobile beds
dam break
How to Cite
Abstract
Direct measurements of bed shear stress have been conducted over rough fixed and mobile sediment beds in dam- break driven swash flows. The comparison between rough fixed and mobile bed results indicated the significant importance of grain borne shear stress component, induced by increased dispersive stress and the momentum transfer by moving sediment grains to the bed. The increase of the averaged peak bed shear stress under mobile sediment beds can be up to 100% of that for fixed beds. The direct incorporation of the shear stress data into the classic Meyer- Peter&Muller (1948) bed load model leads to over-estimate of bed load transport rate and reveals the fact of starved bed conditions applied in the present experiments.References
Allis, M., Blenkinsopp, C., et al., 2014. An investigation of log-law theory for estimating swash zone bed shear stress. Coastal Engineering: Subbmitted.
Bagnold, R.A., 1956. The flow of cohensionless grains in fluids. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 249(964): 235-297.
Baldock, T.E. and Hughes, M.G., 2006. Field observations of instantaneous water slopes and horizontal pressure gradients in the swash-zone. Continental Shelf Research 26(5): 574-588.
Barnes, M.P., 2009. Measurement and Modelling of Swash Zone Bed Shear Stress. PhD Thesis, The University of Queensland, 184 pp.
Barnes, M.P. and Baldock, T.E., 2010. A lagrangian model for boundary layer growth and bed shear stress in the swash zone. Coastal Engineering 57: 385-396.
Barnes, M.P., O'Donoghue, T., et al., 2009. Direct bed shear stress measurements in bore-driven swash. Coastal Engineering 56: 853-867.
Conley, D.C. and Griffin, J.G., 2004. Direct measurements of bed stress under swash in the field. Journal of Geophysical Research 109(C03050): 1-12.
Cowen, E.A., Sou, I.M., et al., 2003. Particle Image Velocimetry Measurements within a Laboratory- Generated Swash Zone. Journal of Engineering Mechanics 129(10): 1119-1129.
Freeman, J.C. and LeMehaute, B., 1964. Wave breakers on a beach and surges on a dry bed. Journal of Hydraulics Division 90(2): 187-216.
Hanratty, T.J. and Campbell, J.A. (1996). Meaurement of wall shear stress. Fluid Mechanics Measurements. R. J. Goldstein, Taylor&Francs: 575-648.
Kolitawong, C., Giacomin, A.J., et al., 2010. Local Shear stress transduction. Review of Scientific Instruments 81(2): 021301.
Li, M.Z., 1994. Direct skin friction measurements and stress partitioning over movable sand ripples. Journal of Geophysical Research 99(C1): 791-799.
McKenna, I.K. and Willetts, B.B., 1993. Adaptation of the near-surface wind to the development of sand transport. Journal of Fluid Mechanics 252: 99-115.
Nemoto, M. and Nishimura, K., 2000. Direct measurement of shear stress during snow saltation. Boundary-Layer Meteorology 100: 147-170.
Nielsen, O., Roberts, S., et al., 2005. Hydrodynamic modelling of coastal inundation. MODSIM 2005 International Congress on Modelling and Simulation, The University of Melbourne, Melbourne, Australia, Modelling and Simulation Society of Australia and New Zealand Inc.
Nielsen, P. (1992). Coastal Bottom Boundary Layers and Sediment Transport. Singapore, World Scientific.
O'Donoghue, T., Pokrajac, D., et al., 2010. Laboratory and numerical study of dambreak-generated swash on impermeable slopes. Coastal Engineering 57(5): 513-530.
Othman, I.K., Baldock, T.E., et al., 2014. Measurement and modelling of the influence of grain size and pressure gradient on swash uprush sediment transport. Coastal Engineering 83: 1-14.
Pope, N.D., Widdows, J., et al., 2006. Estimation of bed shear stress using the turbulent kinetic energy approach-A comparison of annular flume and field data. Continental Shelf Research 26(8): 959- 970.
Pujara, N. and Liu, P.L.-F., 2014. Direct measurements of local bed shear stress in the presence of pressure gradients. Exp Fluids 55(1767): 1-13.
Puleo, J.A., Lanckriet, T., et al., 2012. Near bed cross-shore velocity profiles, bed shear stress and friction on the foreshore of a microtidal beach. Coastal Engineering 68: 6-16.
Rankin, K.L. and Hires, R.I., 2000. Laboratory measurement of bottom shear stress on a movable bed. Journal of Geophysical Research 105(C7): 17011-17019.
Raubenheimer, B. and Elgar, S., 2004. Observations of swash zone velocities: A note on friction coefficients. Journal of Geophysical Research 109: C01027.
Riedel, P.H. and Kamphuis, J.W., 1973. A shear plate for use in oscillatory flow. Journal of Hydraulic Research 11(2): 137-156.
Seelam, J.K. and Baldock, T.E., 2010. Measurements and modeling of direct bed shear stress under solitary waves. Proceeding of nineth International Conference on Hydro-Science and Engineering Chennai, India, ICHE 2010.
Sumer, B.M., Sen, M.B., et al., 2011. Flow and sediment transport induced by a plunging solitary wave. Journal of Geophysical Research 116(C01008): 1-15.