Given that the development of scour downstream of hydraulic structures increases the risk of structural damage,it is important to find cost-effective and environmental approaches to reduce this risk.This study aimed t...Given that the development of scour downstream of hydraulic structures increases the risk of structural damage,it is important to find cost-effective and environmental approaches to reduce this risk.This study aimed to experimentally evaluate the effect of synthetic fibers on the scour profile downstream of a sluice gate with a rigid apron.Experiments were performed with the same Froude number and with different weight percentages of synthetic fibers on both non-cohesive and cohesive sediments.One uniform sand was used as the non-cohesive sediment,and three different cohesive sediments were prepared by mixing different percentages of kaolinite soil with the used sand.The scouring experiments showed that the presence of synthetic fibers did not considerably affect the scour hole dimension in non-cohesive sediments.Evaluation of the scour in the cohesive sediments in silty sand(SM)texture found that an increase in the percentage of silt reduced the scour hole dimensions.The effect of synthetic fibers on scour of SM-texture-based sediments was also investigated,and the results showed that increasing the percentage of synthetic fibers decreased the scour hole dimensions.In addition,the cohesive sediments in SM texture did not have a similar non-dimensional scour profile,and the presence of synthetic fibers did not significantly affect the scour hole.展开更多
The way of producing needle-shaped wolldstonite pow-der has never been released, the key to the matter is to get high enough length to -width ratio of the particle. With φ 50 mm horizontal disk type jet mill,rue carr...The way of producing needle-shaped wolldstonite pow-der has never been released, the key to the matter is to get high enough length to -width ratio of the particle. With φ 50 mm horizontal disk type jet mill,rue carry out a series of experiments, and discover that select-ing reasonable technological operating condition, with the aim of weak-ening colliding pulverizing effect and reinforcing rubbing pulverizing effect, is helpful to improve effectively the L-W radio.展开更多
The mixing characteristics of a Horizontal Momentum Jet in Cross flow （HMJC） were investigated using the CFD code Fluent. The realizable k-ε model was employed for turbulent closure of the Reynolds-averaged Navier-...The mixing characteristics of a Horizontal Momentum Jet in Cross flow （HMJC） were investigated using the CFD code Fluent. The realizable k-ε model was employed for turbulent closure of the Reynolds-averaged Navier-Stokes equations. The computed results, including concentration field and velocity field, agree well with the relations of dimen sional analysis, as well as the experimental results by Sherif and Pletcher, Ali and Yu et al.展开更多
文摘Given that the development of scour downstream of hydraulic structures increases the risk of structural damage,it is important to find cost-effective and environmental approaches to reduce this risk.This study aimed to experimentally evaluate the effect of synthetic fibers on the scour profile downstream of a sluice gate with a rigid apron.Experiments were performed with the same Froude number and with different weight percentages of synthetic fibers on both non-cohesive and cohesive sediments.One uniform sand was used as the non-cohesive sediment,and three different cohesive sediments were prepared by mixing different percentages of kaolinite soil with the used sand.The scouring experiments showed that the presence of synthetic fibers did not considerably affect the scour hole dimension in non-cohesive sediments.Evaluation of the scour in the cohesive sediments in silty sand(SM)texture found that an increase in the percentage of silt reduced the scour hole dimensions.The effect of synthetic fibers on scour of SM-texture-based sediments was also investigated,and the results showed that increasing the percentage of synthetic fibers decreased the scour hole dimensions.In addition,the cohesive sediments in SM texture did not have a similar non-dimensional scour profile,and the presence of synthetic fibers did not significantly affect the scour hole.
文摘The way of producing needle-shaped wolldstonite pow-der has never been released, the key to the matter is to get high enough length to -width ratio of the particle. With φ 50 mm horizontal disk type jet mill,rue carry out a series of experiments, and discover that select-ing reasonable technological operating condition, with the aim of weak-ening colliding pulverizing effect and reinforcing rubbing pulverizing effect, is helpful to improve effectively the L-W radio.
基金Project supported by the programfor New Century Excellent Talents in University (Grant No : NCET-04-0494) ,theNational Natural Science Foundation of China (Grant No :50479068) and the National High Technology Research and Develop-ment Programof China 863 Program(Grant No :2003AA601100)
文摘The mixing characteristics of a Horizontal Momentum Jet in Cross flow （HMJC） were investigated using the CFD code Fluent. The realizable k-ε model was employed for turbulent closure of the Reynolds-averaged Navier-Stokes equations. The computed results, including concentration field and velocity field, agree well with the relations of dimen sional analysis, as well as the experimental results by Sherif and Pletcher, Ali and Yu et al.
