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.
