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...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。展开更多
The major object of this research is the numerical analysis of flow fields over ogee spillway with elliptical crest and the USBR （United States Bureau of Reclamation） in both vertical upstream face state and incline...The major object of this research is the numerical analysis of flow fields over ogee spillway with elliptical crest and the USBR （United States Bureau of Reclamation） in both vertical upstream face state and inclined one with slope 3H：3V. And it also researched the effect of geometry, slopes of curvature of spillway upstream face and water head on the flow field and pressure distribution. In fact Navier-Stokes was used for analyzing flow fields, and VOF （volume of fluid） method was utilized for assigning the free surface, k-e turbulence model RNG was used for analyzing the turbulence field too. Studies show the geometric changes of the spillway pressure distribution and discharge. The spillway with the elliptical crest due to existence of coherence at the curvature of crest created less negative pressure on the crest than USBR crest. So it increased efficiency of spillway discharge about 2% than USBR spillway. Inclining upstream face of spillway affects discharge coefficients and discharge. Hence slope 3H：3V in the upstream face of the crest causes 3.4% more negative pressure in tangent surface and discharges more 1.62% discharge than one of spillway including vertical face. Effect of water head on pressure distribution is simulated on both spillways with elliptical and USBR crest. Numerical results compared to experimental data are satisfactory. The resulted errors of computed discharge compared with experimental data were 0.83%-2% in USBR spillway and 0.29%-2.87% in the elliptical spillway.展开更多
文摘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。
文摘The major object of this research is the numerical analysis of flow fields over ogee spillway with elliptical crest and the USBR （United States Bureau of Reclamation） in both vertical upstream face state and inclined one with slope 3H：3V. And it also researched the effect of geometry, slopes of curvature of spillway upstream face and water head on the flow field and pressure distribution. In fact Navier-Stokes was used for analyzing flow fields, and VOF （volume of fluid） method was utilized for assigning the free surface, k-e turbulence model RNG was used for analyzing the turbulence field too. Studies show the geometric changes of the spillway pressure distribution and discharge. The spillway with the elliptical crest due to existence of coherence at the curvature of crest created less negative pressure on the crest than USBR crest. So it increased efficiency of spillway discharge about 2% than USBR spillway. Inclining upstream face of spillway affects discharge coefficients and discharge. Hence slope 3H：3V in the upstream face of the crest causes 3.4% more negative pressure in tangent surface and discharges more 1.62% discharge than one of spillway including vertical face. Effect of water head on pressure distribution is simulated on both spillways with elliptical and USBR crest. Numerical results compared to experimental data are satisfactory. The resulted errors of computed discharge compared with experimental data were 0.83%-2% in USBR spillway and 0.29%-2.87% in the elliptical spillway.
