钢筋石笼起动流速试验与流场结构数模分析

Critical Velocity Test and Flow-Field-Structure Numerical Analysis of Rock-Filled Steel Cage Under Water

介绍了钢筋石笼起动流速的研究现状,针对其不足,用石笼实际边长代替化引直径,经过理论推导,提出了以拖拽力系数为主要待定参数的钢筋石笼起动流速简化公式,并在此基础上进行了a×a×c形石笼的起动流速水槽试验.通过试验,分析了扁度与稳定性的关系,得到了不同扁度所对应的拖拽力系数值并讨论了底部摩擦力系数f给钢筋石笼稳定性所带来的重要影响.此外,为更好地了解钢筋石笼周围流场的特性,构建了一个透水性绕流数值模型,并以大涡模拟为计算手段,对透水性绕流场进行了三维数值模拟.通过将模拟结果与非透水性绕流场从流场结构、涡体脱落、静压强分布以及拖拽力系数等方面进行定性、定量的对比分析,得到了透水性对流场的具体影响结果.

An introduction to the status of research in the field of the critical velocity of rock-filled steel cage is de-scribed. Considering the deficiencies of studies in the past,a concise formula in which the drag coefficient is the main undetermined parameter is proposed to calculate the critical velocity of rock-filled steel cage. In the formula,cage length,instead of the transformed diameter,is employed. A flume test is also carried out for the cage in the shape of a ＆#215; a ＆#215; c . According to the experimental results,the relationship between the flatness and the stability of the cage under water is analyzed,and the value of drag coefficient under different flatness is obtained. The great influence of friction coefficient on the stability of rock-filled steel cage is also discussed. Besides,for a better understanding of the flow field around the cage,a large eddy simulation is employed to simulate the three dimensional structure of the flow passing a pervious cubic-blunt body at Re=2.2＆#215;104. Thus,the characteristics of this kind of flow field and its concrete effects are concluded from the aspects of flow field structure,vortex shedding,drag coefficient and static pressure distribution.