摘要
应用激光测速仪对齿形尾坎消力池下游水流的紊动特性进行了系统试验研究,并与梯形尾坎作对比试验。分析了紊动强度、紊动能量、功率谱密度函数及实际消能率等,求出这些紊动参数沿水深的分布和沿流程转换与衰减的规律以及与佛劳德数的关系,规律性较好,得出齿形尾坎的紊动参数均比梯形尾坎明显减小;由于槽齿分流,齿形尾坎不仅改善了流速分布,而且紊动交界面增多,衰减紊动能的作用较强,因而消能效率比梯形尾坎者大,故冲刷深度比梯形尾坎小的多,初步探明了消能机理。
By using the Laser Doppler Velocimeter of polarization differentiation and Jsp-1 signal processor-counter, an experimental study of the turbulent flow characteristics downstream of the stilling basin with dentated sills (Rehbock Sills) was carried out. Comparative studies of that with the trapezoidal profile sills in the same hydraulic conditions were-made. Based on these results, the turbulence intensity, turbulent energy, density function of power spectral, frequency characteristics and the actual energy dissipation rate of the forced hydraulic, jump were analyzed. The vertical distribution, the longitudinal transformation and the decay pattern of these turbulence parameters were found to have good relations with Froude numbers. Moreover, it was found that the turbulent energy, and turbulence intensity of the flow with dentated sills were much less than that with trapezoidal sills in all sections. It is evident that, because of the dentation which divides, the flow, the dentated sills not only improve the velocity distribution, but also increase the intermittent zones between the secondary flow of the rollers and primary flow and make the turbulence energy decay faster. Hence, comparing with trapezoidal sills, the energy dissipation rate of dentated sills is larger and the scour holes are shallower, The mechanism of energy dissipation was explained.
出处
《力学学报》
EI
CSCD
北大核心
1989年第5期530-538,共9页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家教委重点科研基金
关键词
齿形尾坎
消力池
消能
紊动
特性
dentated sills, turbulence intensity, turbulent energy, actual energy dis-sipation rate, mechanism of energy dissipation.
