An oil flume in combination with a 100 Hz Particle Image Velocimetry system has been used to study entrainment of 11 turn diameter spherical Nylon particles. The flow field near the bed and around sediment particles holds essential information for studying entrainment mechanics, but measurements in water are often hampered by a lack of adequate resolution, particularly for smaller particle sizes. The higher viscosity of oil compared to water increases length scales, allowing water flows to be modelled with much larger sediment sizes and deeper near-bed flow layers. The 11 mm diameter particles used in the present oil flow experiments are dimensionally equivalent to 0.74 mm diameter quartz particles in water flow. Analysis of the flow field at the instant of bed particle movement indicates that sweep structures (higher than averaged streamwise velocity combined with bed-directed vertical velocity) are the dominant mechanism of entraining particles for the bed geometry and flow regimes studied.
|Title of host publication||River Flow 2006, v. 1, Taylor and Francis, London|
|Place of Publication||River Flow 2006, v. 1, Taylor and Francis, London|
|Number of pages||8|
|Publication status||Published - 2006|