Experimental investigations of interaction between mudflow and an obstacle
The present study aimed at determining local values of the mudflowvelocity and pressure in the vicinity of a structure subjected to a mudflowimpact, as well as the changes in these variables over time, for a given incident mudflow characterized by its Froude number. Experiments were set up to run free-surface unsteady mudflows in a laboratory flume where a simple barrier had been installed. The model fluid was a Carbopol solution, which behaves as a yield-stress fluid. As this fluid is transparent, particle image velocimetry (PIV) techniques were applied to measure the local velocities inside the simulated mudflow. Additionally, the pressure applied to the structure by the mudflow impact was measured by a pressure sensor installed inside the obstacle body. This experimental study has demonstrated the existence of two distinct impact regimes associated with subcritical and supercritical incident mudflows, respectively, which present either a gentle increase in pressure (subcritical mudflow) or a jet flow and a sharp increase followed by a sharp decrease in pressure (supercritical mudflow). In the subcritical mudflow case, the dead zone with immobile fluid, which forms upstream of the obstacle, seems to play an important role in the transmission of stresses to the structure. The study of the dynamic pressure also indicated a substantial increase in the drag coefficient for low Froude number values.
mudflow flow-structure interaction impact regimes pressure Froude number
D. Tiberghien D. Laigle M. Naaim E. Thibert F. Ousset
Snow Avalanche and Torrent Control Research Unit, Cemagref, Saint Martin dHeres Cedex, France
国际会议
成都
英文
281-292
2007-05-17（万方平台首次上网日期，不代表论文的发表时间）