上游边坡系数对折线型实用堰流量系数的影响
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摘要
为系统地分析无侧收缩折线型实用堰(简称折线堰)上游边坡系数对自由堰流流量系数的影响规律,采用VOF(volume of fluid method)方法和RNG k-ε紊流模型对下游边坡直立、上游边坡系数依次为0、0.3、0.5、0.8、1.0、1.5和2.0的7个折线堰模型进行数值模拟。数值模拟结果表明,随着堰顶总水头的增加,水面线曲率减小,流量系数增大,同时上游边坡系数对流量系数的影响逐渐减小。采用多元非线性回归方法建立了含有上游边坡系数的折线堰流量系数计算公式,该公式在堰顶总水头一定时,流量系数随着上游边坡系数先增大后减小。
To systemically study the effect of varying slope coefficients in the upstream side on the discharge coefficient at free overflow over a broken-line practical weir with vertical downstream face and without lateral contraction,different slope coefficients of upstream side,including 0,0. 3,0. 5,0. 8,1. 0,1. 5 and 2. 0,are simulated by the volume of fraction( VOF) method and the RNG k-ε turbulence model. Numerical results show that the rising of total head H0 reduces the curvature of free surface profile and increases the discharge coefficient.Meanwhile,the influence of slopes in upstream side on the discharge coefficient decreases with H0. Furthermore,a discharge coefficient formula including the variable slope coefficient of upstream side is derived based on the method of non-linear regression,in which as the slope coefficient of upstream side increases,the discharge coefficient increases firstly and then decreases for a given H0.
To systemically study the effect of varying slope coefficients in the upstream side on the discharge coefficient at free overflow over a broken-line practical weir with vertical downstream face and without lateral contraction,different slope coefficients of upstream side,including 0,0. 3,0. 5,0. 8,1. 0,1. 5 and 2. 0,are simulated by the volume of fraction( VOF) method and the RNG k-ε turbulence model. Numerical results show that the rising of total head H0 reduces the curvature of free surface profile and increases the discharge coefficient.Meanwhile,the influence of slopes in upstream side on the discharge coefficient decreases with H0. Furthermore,a discharge coefficient formula including the variable slope coefficient of upstream side is derived based on the method of non-linear regression,in which as the slope coefficient of upstream side increases,the discharge coefficient increases firstly and then decreases for a given H0.
引文
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[20]VACCINE D V,王世夏.模型缩尺和流量系数[J].水利水电科技进展,1981,1(2):37-44.(VACCINE D V,WANG Shixia.Model scale and discharge coefficient[J].Advancesin Science and Technology of Water Resources,1981,1(2):37-44.(in Chinese))
[21]ISAACS L T.Effects of laminar boundary layer on a model broad-crested weir[J].Nasa Sti/recon Technical Report N,1981,83:1-20.
[22]RANGARAJU K G,SRIVASTAVA R,POREY P D.Scale effects in modelling flow over broad-crested weirs[J].Irrigation and Power,1990,47:101-106.
[23]HIRT C W,NICHOLS B D.Volume of fluid(VOF)method for the dynamics of free boundaries[J].Journal of Computational Physics,1981,39(1):201-225.
[24]YAKHOT V,ORSZAG S A.Renormalization group analysis of turbulence.I.basic theory[J].Journal of Scientific Computing,1986,1(1):3-51.
[25]王福军.计算流体动力学分析:CFD软件原理与应用[M].北京:清华大学出版社,2004.
[2]童海鸿,李梦成,丁新求.低堰体型与泄流能力关系的初步研究[J].长江科学院院报,2011,28(4):25-28.(TONG Haihong,LI Mengcheng,DING Xinqiu.Relation between low weir shape and discharge capacity[J].Journal of Yangtze River Scientific Research Institute,2011,28(4):25-28.(in Chinese))
[3]李炜.水力计算手册[M].2版.北京:中国水利水电出版社,2006.
[4]李家星,赵振兴.水力学[M].南京:河海大学出版社,2001.
[5]INOZEMTSEV Y P.Cavitation destruction of concrete and protective facings under natural conditions[J].Power Technology and Engineering,1969,3(1):35-42.
[6]童海鸿,兰芙蓉.堰高对低堰泄流能力影响的分析[J].人民长江,2002(11):20-21.(TONG Haihong,LAN Furong.Analysis of the effect of weir height on discharge capacity of low weirs[J].Yangtze River,2002(11):20-21.(in Chinese))
[7]RAMAMURTHY A,TIM U,RAO M.Characteristics of square-edged and round-nosed broad-crested weirs[J].Journal of Irrigation and Drainage Engineering,1988,114(1):61-73.
[8]BOS M G.Discharge measurement structures:working group on small hydraulic structures[M].Wageningen:International Institute for Land Reclamation and Improvement,1978.
[9]基谢列夫.水力学流体力学原理[M].北京:水利电力出版社,1983.
[10]童海鸿,艾克明,丁新求.折线型实用堰过流能力研究[J].中国农村水利水电,2002,19(2):7-10.(TONG Haihong,AI Keming,DING Xinqiu.Discharge capacity of broken-line practical weir[J].China Rural Water and Hydropower,2002,19(2):7-10.(in Chinese))
[11]SINGER J.Square-edged broad-crested weir as a flow measurement device[J].Water and Water Engineering,1964,68(6):229-235.
[12]FARHOUDI J,SHAH ALAMI H.Slope effect on discharge efficiency in rectangular broad crested weir with sloped upstream face[J].International Journal of Civil Engineering,2005,3(1):58-65.
[13]AZIMI A H,RAJARATNAM N.Discharge characteristics of weirs of finite crest Length[J].Journal of Irrigation and Drainage Engineering,2009,139(1):1081-1085.
[14]GOODARZI E,FARHOUDI J,SHOKRI N.Flow characteristics of rectangular broad-crested weirs with sloped upstream face[J].Journal of Hydrology and Hydromechanics,2012,60(2):87-100.
[15]张绍芳.低堰溢流能力计算[J].水利学报,1982,13(11):53-57.(ZHANG Shaofang.Calculation on overflow capacity of low weirs[J].Journal of Hydraulic Engineering,1982,13(11):53-57.(in Chinese))
[16]武汉水利电力学院水力学教研室.水力计算手册[M].北京:中国水利水电出版社,1983.
[17]HAUN S,OLSEN N R B,FEURICH R.Numerical modeling of flow over trapezoidal broad-crested weir[J].Engineering Applications of Computational Fluid Mechanics,2011,5(3):397-405.
[18]SARGISON J E,PERCY A.Hydraulics of broad-crested weirs with varying side slopes[J].Journal of Irrigation and Drainage Engineering-ASCE,2009,135(1):115-118.
[19]PAIK J,LEE N J.Numerical modeling of free surface flow over a broad-crested rectangular weir[J].Journal of Korea Water Resources Association,2015,48(4):281-290.
[20]VACCINE D V,王世夏.模型缩尺和流量系数[J].水利水电科技进展,1981,1(2):37-44.(VACCINE D V,WANG Shixia.Model scale and discharge coefficient[J].Advancesin Science and Technology of Water Resources,1981,1(2):37-44.(in Chinese))
[21]ISAACS L T.Effects of laminar boundary layer on a model broad-crested weir[J].Nasa Sti/recon Technical Report N,1981,83:1-20.
[22]RANGARAJU K G,SRIVASTAVA R,POREY P D.Scale effects in modelling flow over broad-crested weirs[J].Irrigation and Power,1990,47:101-106.
[23]HIRT C W,NICHOLS B D.Volume of fluid(VOF)method for the dynamics of free boundaries[J].Journal of Computational Physics,1981,39(1):201-225.
[24]YAKHOT V,ORSZAG S A.Renormalization group analysis of turbulence.I.basic theory[J].Journal of Scientific Computing,1986,1(1):3-51.
[25]王福军.计算流体动力学分析:CFD软件原理与应用[M].北京:清华大学出版社,2004.