水流作用力垂向变化对块体抛放影响的综合研究

考虑块体在水体中的相对位置,综合研究了不同水深区域内水流作用力系数的变化关系。在自由水表面和河床壁面附近区域,应分别考虑水表面波动和边界层对垂线流速分布的影响,由平均流速计算得出的拖曳力系数与相对位置基本呈递增关系,而上举力系数递减;介于上述区域之间时,近似认为拖曳力系数和上举力系数不随相对位置变化。因此,在受力分析以计算石块或沙袋的抛掷位移时,应考虑水流流动作用力垂向不断变化的特点。

Influence of Vertical Variation of Hydrodynamic Forces on Block Setting

The hydrodynamic force coefficients in vertical different fluid regions are studied based on the relations between the force coefficients and the relative position.Within the regions nearby the channel bed and the free water-surface,the infiuence of boundary layer and water-surface should be taken into account correspondingly.The drag coefficient calculated by the vertical average velocity is approximately incremental with the relative position,while lift coefficient decreased;between these two regions,the drag and lift coefficients keep constant with the relative position.Therefore,it should be considered that the character of hydrodynamic force changing continuously,when analyzing forces to calculate the displacement of setting block.