摘要
为研究矩形渠道水流的阻力规律,采用了3种不同粗糙度的人工加糙渠道进行试验。研究结果表明在均匀流条件下,对同一粗糙度明渠,水力条件变化时糙率系数不是恒定不变的,它会随着流量的加大而呈对数减小,随着渠道宽深比的增大而呈对数增大,同时随着雷诺数Re和弗汝德数Fr的增加而呈幂函数减小。同时表明,不同的壁面粗糙度对糙率系数影响很大,进而影响水流的水力特性。即流量相同条件下,当壁面粗糙度增大时,断面水深增大,平均流速减小,雷诺数和弗汝德数均减小。并根据试验资料拟合出了糙率系数和等效粗糙度之间的关系式。
In order to analyze the friction law of the rectangle channel,this experimental research is carried out in an artificial rough-wall channel under three different roughness coefficients The experimental results indicate that,under an uniform flow,the roughness coefficient is not constant in the same roughness channel when the hydraulic condition changes.It increases logarithmically when the width-depth ratio of the channel increases,and decreases logarithmically when the flow increases,or decreases followed a power function when the Reynolds and Froude number increases,respectively.Meanwhile,the results show that different wall roughness has an obvious effect on the roughness coefficient,and then affects the hydraulic characteristics.Namely,water depth increases when the wall roughness increases,while mean velocity of flow and the Reynolds and Froude decrease under the same discharge condition.At last,the relation formula between roughness coefficient and equivalent roughness is given according to the experimental data.
出处
《长江科学院院报》
CSCD
北大核心
2011年第1期34-38,共5页
Journal of Changjiang River Scientific Research Institute
基金
国家973计划课题(2007CB407201)
国家自然科学基金重点项目(40335050)
关键词
阻力规律
糙率系数
水力特性
friction law
roughness coefficient
hydraulic characteristics
