In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including ...In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including 17 tests was conducted to estimate the variation of the discharge coefficient due to variation of the longitudinal slope. It was shown that the discharge coefficient is significantly increasing with the increase of the slope by more than 90% or 75% and 80% or 70% for weir and spillway in case of excluding or including the approach velocity head, respectively. Also, CFD （computational fluid dynamics） with a help of Comsol-multyphsics program was used to simulate the problem. The program explained that the linear distribution of the hydraulic pressure changes to a non-linear distribution as the longitudinal slope is considered. Consequently, the values of the discharge coefficient are also affected.展开更多
There are N domains Dj(j=0,1,...,N-1) of different physical parameters in the whole space and their interfaces S,are non-horizontally smooth curved surfaces. The following boundary problem is called Hclinholiz boundar...There are N domains Dj(j=0,1,...,N-1) of different physical parameters in the whole space and their interfaces S,are non-horizontally smooth curved surfaces. The following boundary problem is called Hclinholiz boundary problem:The analytical solution of the above problem is given in this paper.展开更多
A method to compute the daily, monthly and yearly extra terrestrial solar irradiation (S_(ot), S_(otm), S_(oty)) on tilted surfaces for arbitrary latitude is determined. The systematic distributional charts of S_(ot),...A method to compute the daily, monthly and yearly extra terrestrial solar irradiation (S_(ot), S_(otm), S_(oty)) on tilted surfaces for arbitrary latitude is determined. The systematic distributional charts of S_(ot), S_(otm) and S_(oty) on a global scale are given for the first time. Some specific rules are discovered: (ⅰ) The latitudinal variation curves of the slope irradiation for different azimuths converge polewards. (ⅱ) At the North (South) Pole the different azimuth's values of the irradiation for a given slope and time period are identical. (ⅲ) At the equinoctial dates, the S_(ot) on the east (or west) vertical surface does not vary with latitude (except poles). (ⅳ) If some latitude range in the polar regions is all in the polar day at a certain date, the S_(ot) on the east (or west) vertical surface in the date is also not varying with latitude in the range. (ⅴ) The yearly irradiation S_(oty) on the east (or west) vertical surface maintains the same value for any latitude.(ⅵ) The extraterrestrial irradiation in the Southern and Northern Hemispheres is in a reverse-approximate symmetry.展开更多
The fuel delivery laws of horizontal tanks are no longer adequate for efficient supply under complex flight conditions,while the supply characteristics of non-horizontal tanks are not sufficiently explored.In this wor...The fuel delivery laws of horizontal tanks are no longer adequate for efficient supply under complex flight conditions,while the supply characteristics of non-horizontal tanks are not sufficiently explored.In this work,the piston-driven fuel supply devices with external slit-shaped and novel built-in cube-,sphere-,and dome-shaped intakes were selected as the research objects.The conveying sensitivity of devices at different tilt angles was investigated using two-fluid model.The results indicate that as the tilt angle increases from 0◦to 90◦,the fluctuation in mass flow rate of powder under the cube-,sphere-,and dome-shaped intakes increases by about 53.8%,46.6%,and 35.0%,respectively,while the slit-shaped intake decreases by about 1.0%.The gas under the built-in intake migrates from the head of the device to the outlet,while the gas under the external intake is distributed near the wall of the conical convergence section,and the fluctuations in pressure and relative pressure drop of the former are more intense than those of the latter.At varying tilt angles,the area of gas phase under external intake is approximately 15 times that of the built-in.At low tilt angles(0◦and 30◦),the variations in gas-solid velocities and powder concentration are similar for the domeand slit-shaped intakes.As the tilt angle increases,the fluctuation in these two physical quantities in the cubeand sphere-shaped intakes is larger than in other cases.At a high tilt angle(90◦),the built-in cube-shaped intake exhibits the least satisfactory supply performance.展开更多
文摘In this work, experiment efforts were devoted to study the effect of the longitudinal slope of channel on the discharge coefficient for ogee spillway and broad crested weir. A comprehensive laboratory study including 17 tests was conducted to estimate the variation of the discharge coefficient due to variation of the longitudinal slope. It was shown that the discharge coefficient is significantly increasing with the increase of the slope by more than 90% or 75% and 80% or 70% for weir and spillway in case of excluding or including the approach velocity head, respectively. Also, CFD （computational fluid dynamics） with a help of Comsol-multyphsics program was used to simulate the problem. The program explained that the linear distribution of the hydraulic pressure changes to a non-linear distribution as the longitudinal slope is considered. Consequently, the values of the discharge coefficient are also affected.
文摘There are N domains Dj(j=0,1,...,N-1) of different physical parameters in the whole space and their interfaces S,are non-horizontally smooth curved surfaces. The following boundary problem is called Hclinholiz boundary problem:The analytical solution of the above problem is given in this paper.
文摘A method to compute the daily, monthly and yearly extra terrestrial solar irradiation (S_(ot), S_(otm), S_(oty)) on tilted surfaces for arbitrary latitude is determined. The systematic distributional charts of S_(ot), S_(otm) and S_(oty) on a global scale are given for the first time. Some specific rules are discovered: (ⅰ) The latitudinal variation curves of the slope irradiation for different azimuths converge polewards. (ⅱ) At the North (South) Pole the different azimuth's values of the irradiation for a given slope and time period are identical. (ⅲ) At the equinoctial dates, the S_(ot) on the east (or west) vertical surface does not vary with latitude (except poles). (ⅳ) If some latitude range in the polar regions is all in the polar day at a certain date, the S_(ot) on the east (or west) vertical surface in the date is also not varying with latitude in the range. (ⅴ) The yearly irradiation S_(oty) on the east (or west) vertical surface maintains the same value for any latitude.(ⅵ) The extraterrestrial irradiation in the Southern and Northern Hemispheres is in a reverse-approximate symmetry.
基金supported by the National Natural Science Foundation of China(grant No.12102161)the Key Research Program of Jiangxi Province,China(grant No.20232BBE50005)the Natural Science Foundation of Jiangxi Province,China(grant No.20224BAB214060).
文摘The fuel delivery laws of horizontal tanks are no longer adequate for efficient supply under complex flight conditions,while the supply characteristics of non-horizontal tanks are not sufficiently explored.In this work,the piston-driven fuel supply devices with external slit-shaped and novel built-in cube-,sphere-,and dome-shaped intakes were selected as the research objects.The conveying sensitivity of devices at different tilt angles was investigated using two-fluid model.The results indicate that as the tilt angle increases from 0◦to 90◦,the fluctuation in mass flow rate of powder under the cube-,sphere-,and dome-shaped intakes increases by about 53.8%,46.6%,and 35.0%,respectively,while the slit-shaped intake decreases by about 1.0%.The gas under the built-in intake migrates from the head of the device to the outlet,while the gas under the external intake is distributed near the wall of the conical convergence section,and the fluctuations in pressure and relative pressure drop of the former are more intense than those of the latter.At varying tilt angles,the area of gas phase under external intake is approximately 15 times that of the built-in.At low tilt angles(0◦and 30◦),the variations in gas-solid velocities and powder concentration are similar for the domeand slit-shaped intakes.As the tilt angle increases,the fluctuation in these two physical quantities in the cubeand sphere-shaped intakes is larger than in other cases.At a high tilt angle(90◦),the built-in cube-shaped intake exhibits the least satisfactory supply performance.
