筏式养殖区流速垂向分布公式的试验研究

Experimental Research on Formulas of Velocity Distribution in Vertical Direction in Raftculture Zones

以模型长度比尺λl=lp/lm=20(lp,lm分别为原型和模型的长度)筏式养殖模型布置于矩形水槽中进行试验,对养殖区的典型位置进行流速垂向分布测量.首先利用明渠流理论,以常用对数函数曲线与抛物线曲线对流速垂向分布进行初步拟合与分析,按影响程度分为养殖区强影响区、中影响区与弱影响区.然后在箱线图上拟合公式来确定公式的系数,得到强影响区与中影响区流速垂向分布的抛物线型公式,前者的公式系数大于后者;得到弱影响区流速垂向分布的对数函数型公式.最后对比分析了养殖密度的影响,养殖密度增大,抛物线型公式的相应系数增大,对数函数型公式系数上、下限亦增大.

Physical experiments are carried out in a rectangular flume with a length scale of 20 models, and the velocity is measured in vertical particular depth. First, the velocity distributions in vertical direction are initial fitted by curves of the parabolic and logarithmic formula based on the theory of open channel flow and analyzed, the strongly affected zones, moderately affected zones and weakly affected zones are classified from the effect degree. Then, the formula coefficients are deduced by the method of Box-plot fitting, and the formulas of vertical velocity distribution are obtained with parabolic equation in strongly and moderately affected raft zones and coefficients of the former larger than the latter;however, the logarithmic equation is more suitable to weakly affected zones. Finally, the analysis on effect of aquiculture density leads to the conclusion on the parabolic coefficients and the range of logarithmic coefficients increase with the density increasement.