Synopsis |
For an isolated cylinder subject to steady current, the primary governing parameter is the Reynolds number (inertia force/viscous force, = UD/nu). Within a very large range of Re (1000~3x10^5), the drag coefficient of the cylinder remains nearly a constant of 1.2, and then experiences a sudden reduction to about 0.3 in a very narrow range (3x10^5~5x10^5). This sudden reduction is the so-called Drag Crisis. In this seminar, an investigation about the drag crisis of a cylinder near a plane boundary will be reported. The research was carried out through both numerical and experimental method. The results show that the drag crisis for a cylinder near a plane boundary is significantly affected by the gap to diameter ratio. With the reduction of the gap ratio, the critical Reynolds number for drag crisis becomes lower gradually and the range of the drag reduction becomes less. This is attributed to the increase of turbulence intensity at the pipe level with the reduction of the gap to diameter ratio. |
Biography |
Lecture at School of Civil, Environmental and Mining Engineering, The University of Western Australian (UWA).Hongwei got his PhD from UWA in 2010. The PhD thesis topic was NUMERICAL MODELLING OF FLOW CHARACTERISTICS ON A CYLINDER SUBJECT TO OSCILLATORY FLOW He worked as a Research Associate at UWA from 2010 to 2015, working on a Joint Industry Project to investigate the stability of subsea pipeline on an erodible seabed.Hongwei was appointed a lecture position at UWA |
