Applied Mechanics and Materials Vols. 641-642

Abstract: Dongbei waterway in the lower reach of Yangtze River includes three waterways: Hukou waterway, Heng waterway and Zhi waterway. For a long time the documents about the evolution of measured data in based mainly on topographic information and it is insufficient materials actually measured about the character of water flow. In order to make up the incomplete measured documents, it is intended herein to make calculation of character of water flow by means of mathematic model. The results show that, there are overflows to various extents for the side shoal at Sizhouwei under different discharge. It appears crossing troughs in the left to the side shoal at Sizhouwei. The bigger flow velocity of lower shoal and its left rim is possible for being washed out.

Abstract: Rice growth model of ORYZA2000 was introduced, we used field datas to verify the parameters. The aim is to check the adaptability of model, when it is applied to simulate dry matter, leaf area and yield under water and nitrogen managements. The results showed that, the model can simulate dry matter accumulation preferable, in which the observed dry matter of aboveground, leaf and sheath fit well with simulated results. But the simulated yield is higher then observed, may be the reason due to the rice lodging at later stages. While the simulated leaf area is lower than observed, the reason is that we have the dead leaves are counted in measuring. ORYZA2000 provides a powerful tool to explore the impact on the environment as well as water-saving irrigation of rice under optimal water and fertilizer managements.

Abstract: Dongbei waterway in the lower reach of Yangtze River includes three waterway: Hukou waterway, Heng waterway and Zhi waterway. The evolvement trend based on the measured data show that the right branch of Xiasanhaozhou is developed and the shallow shoal at the head of Xiasanhaozhou is scoured along with the right branch be rushed and ratio of diversion flow increase which have negative effect on transition shoals. In order to analysis the effect of evolvement trend on the channel conditions of transition shoals, this paper adopt cognitive calculation on water flow of Dongbei waterway using mathematic model. The results show that, the development of right branch of Xiasanhaozhou and the shallow shoal cutting at the head of Xiasanhaozhou decrease velocity of transition sections, decrease the diversion flow of the left branch of Xiasanhaozhou, and increase the diversion flow of the head of Xiasanhaozhou which have negative effect on transition shoals.

Abstract: Monthly potential evapotranspiration (ET₀) from 1957 to 2010 is estimated with Penman-Monteith method in four stations in hilly area of central Sichuan, China. Results show that ET₀ has a decrease, temperature has a significant increase, relative humidity has a significant decrement, sunshine duration and wind speed have very significantly downward trends. Climate tends to warming and drying in recent 50 years.

Abstract: The rough model method is successfully used to design a pressurized rectangular shaped conduit characterized by two linear dimensions. In this study, the focus is on the calculation of the horizontal linear dimension of the conduit. In a first step, the method is applied to a referential rough model in order to establish the relationships that govern its hydraulic characteristics. The obtained equations are of the third degree and are easily solved by trigonometric and hyperbolic functions. In a second step, these equations are used to easily deduce the linear dimension sought by introducing a non-dimensional correction factor. Practical example is taken to enable the hydraulic engineer to better understanding the advocated method and to observe the facility with which design of such a geometric profile can be performed. The calculation uses a strict minimum of data measurable in practice, in particular the absolute roughness.

Abstract: Sediment settling velocity is an important parameter in particle suspension and indispensable link of hyperconcentrated flow as well as basic theory support for efficient sediment transport of Xiaolangdi Reservoir. This paper has adopted current sediment sample in Xiaolangdi Reservoir to take still water settling experiment, observed carefully silt sediment distribution during different settling duration under various initial concentrations, analyzed common settling velocity calculation method, and adopted settling duration curve method as calculation method to obtain a constant settling velocity of free settling section. Typical settling velocity that is obtained from experiments makes supplement and fitness to settling velocity formula of the existing groups of sediment sample, amends the formula coefficient, further explore the settling characteristics and settling velocity of fine particle mixed viscous sediment with water concentration change, and meanwhile this paper researched settling distance impact on settling velocity, existing sediment group settling transition to mesh settling critical transition silt concentration of Xiaolangdi Reservoir.

Abstract: This passage introduces the formation process of scour hole, analyzes the main factors contributed to the local scour hole’s depth and classifies today’s calculation methods of scour depth into three categories. Then, given the conditions where those methods can be applied and drawbacks of those methods, this article also recommends some suggested formula in calculation.

Abstract: The problem that the actual operation flow rate of inverted siphon in Xinjiang can not meet the need of the design requirement has always been discussed. After comparing Cole Brook - White Formula, Jain,A.K Formula and Hazen-Williams Formula, and taking FRP pipes as the research object, this paper attempts to make use of different formulas to calculate friction loss of inverted siphon, compare and analyze the calculation results with the measured data of years of operation. Finally, it is proved that Hazen-Williams formula has relatively higher accuracy in calculating head loss and the frictional coefficient of friction to different diameters has been obtained, which can offer reference to the inverted siphon’s engineering design of FRP pipes.

Abstract: From the perspective of quasi-public goods, this paper studies the investment of the farmland water infrastructure, and uses game theory to analyze government and private investors. It is found that in the presence of investment constraints, the government can not complete quasi-public goods investment in farmland water infrastructure independently, so the government needs to provide appropriate policies to increase the marginal benefit of private investors to attract private cooperation. Then this paper compares spontaneous investments and incentive investment from private investors, and concludes with policy recommendations.

Abstract: With the continuous development of large-scale, high-speed ship, considering economy and security of the ship, propeller design and performance research are of importance. In this paper, the best propeller is obtained by using the propeller design software HydroComp PropExpert and HydroComp PropCAD. Propeller geometry model is generated by Solidworks. Applying computational fluid dynamics method (CFD), we can take numerical simulation for the flow around the propeller. Finally, with the help of the software ANSYS, hydrodynamic performance of the design propeller can be forecasted. The results from the calculation and analysis can provide some reference for engineering practical problems and theoretical study.