摘要
迷宫式侧堰具有较大的泄流能力,广泛应用于流量控制、农田灌溉和排水系统.为研究三角迷宫式侧堰的复杂水力特性、泄流规律及泄流影响因素,本研究首先基于FLOW-3D软件和RNG k-ε湍流模型,对侧堰的15种工况进行数值模拟计算,获得侧堰水面流态、流速分布等水力特性.同时,通过白金汉π定理推出影响迷宫式侧堰流量系数的无量纲参数,探究流量系数C_(d)与无量纲参数之间的变化规律,利用人工智能遗传规划(Genetic Programming,GP)算法拟合出流量系数计算公式.结果表明:主渠道内水流为缓流,堰顶角θ较小时,二次流使得水面流态变化,流速在靠近侧堰时发生急剧变化,堰内产生回流.随着θ的增大,堰顶上方水舌从对称分布变为偏右侧下泄,堰内回流现象消失;C_d随上游弗劳德数Fr和溢流前沿与堰顶水深之比l/h_(1)的增加而减小,随堰高与堰上水头之比p/h_(1)的增加而增加,θ越大,C_(d)变化趋势越大;流量系数预测公式在测试阶段的决定系数R^(2)=0.913,均方根误差RMSE=0.045,流量系数预测值与试验值的散点图拟合效果良好,数据点分布均匀且关于拟合线对称,表明GP模型得出的结果较为准确,满足灌区量水精度要求.该研究成果可为迷宫式侧堰在实际工程中的应用提供理论依据和技术支撑.
The labyrinth side weir has a large discharge capacity.It is widely used in flow control,farmland irrigation and drainage systems.In order to study the complex hydraulic characteristics for the triangular labyrinth side weir,the variation law of the discharge and the factors affecting the discharge,in this study we firstly carry out the numerical simulations regarding the hydraulic performance of a labyrinth side weir in 15 working conditions based on FLOW-3D software and RNG k-turbulence model.Its purpose is to obtain the hydraulic characteristics such as water surface flow pattern and velocity distribution of the side weir.Secondly,the dimensionless parameters affecting the discharge coefficient Ca of the labyrinth side weir are derived by Buckingham r theorem.Then the change rule between the Ca and the dimensionless parameters is explored.Finally,the calculation formula for discharge is obtained by developing artificial intelligence algorithm Genetic Programming(GP).The results show that the water in the main channel is in tranquil flow.When the weir crest angle is small,the secondary flow changes the flow pattern and direction of the water surface.The flow velocity changes sharply at the position close to the side weir,and vortexes occur inside the side weir.With the increase of o,the water tongue above the side weir changes from symmetric distribution to the right side leakage,and the backflow inside the side weir gradually disappears.C,decreases with the increase of the upstream Froude number(Fr)and the ratio of the overflow front to the upstream water depth(p/h_(1)),and increases with the increase of the ratio of the weir height to the upstream water depth(p/h_(1)).The greater the 3,the greater the change of C_(d).The model evaluation results show that the calculation formula has the determination coefficient R^(2)=0.913 and the root mean square error RMSE=0.045.Moreover,the predicted discharge coefficient C_(d)has a great fiting consistency with the experimental scatter diagram,with the data points evenly
作者
李珊珊
曹顶业
沈桂莹
李国栋
LI Shanshan;CAO Dingye;LI Guodong;SHEN Guiying(State Key Laboratory of Ecological Water Conservancy in Arid Areas of Northwest China,Xi'an University of Technology,Xian 710048,Shaanxi,China)
出处
《力学季刊》
CAS
CSCD
北大核心
2024年第1期177-186,共10页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(52079107)
陕西省自然科学基金(2023-JC-QN-0395)
陕西省教育厅专项(22JK047)
西安理工大学优硕种子基金(310/252082213)。
关键词
三角迷宫式侧堰
水力特性
遗传规划算法
数值模拟
triangular labyrinth side weirs
hydraulic parameters
genetic programming algorithm
numerical simulation
