Applied Mechanics and Materials Vols. 444-445

Abstract: Gas anchor is also known as downhole oil and gas separator. It plays a role of separating the gas and oil before the fluid flows into the pump, thus to eliminate the influence of gas and improve pump efficiency. It can also extend the lifetime of the equipment and increase the oil well output. On the analysis of factors affecting the efficiency of gas anchor, I built 3D models in Gambit on the basis of the blueprint of multi-cup isoflux gas anchor. I used Fluent to calculate the multi-cup isoflux gas anchor separation of oil and gas with laminar flow model. Then I got the distribution of speed and pressure in the multi-cup isoflux gas anchor and derived the formula of local resistance ratio. Learned that on the application of the multi-cup isoflux gas anchor the pumping wells pump efficiency enhances on an average of more than 25%.

Abstract: Karst rocky desertification is one of the serious environment problems in southwest of China. In this study, a typical county with karst rocky desertification which located in Southeast of Yunnan province is selected as a work area at first. Based on the datum collection about land use status and field verification surveying in study area, the technique of remote sensing image processing and GIS spatial analysis was integrated used to monitor the karst rocky desertification status and got its information in different degree. Analysis for karst rocky desertification spatial distributing, the main result is that there is more amount proportion of karst rocky desertification land cover in case study area and these large numbers patches of karst rocky desertification mosaic beset in the different land use types, such as forest, plantation and artificial town or other infrastructure building. So it is stringent need to deepen research the karst rocky desertification development and its spatial expand. Another result include that remote sensing monitoring for the karst rocky desertification is one of the important advance technique method, but it also need to fuse more another assistant information according to the actual condition in case study area, for example, the land use status in quo is a good means to assistant remote sensing monitoring karst rocky desertification by spatial restrict effect.

Abstract: For a high-rise complex structure built at an earthquake zone, response characteristics to an earthquake action are always needed to be as an important index to evaluate its dynamical performances. This article carried out a three-dimensional dynamical response analyses of a large-scale complex sluice-dam structure by using the software of ANSYS under a strong earthquake excitation by nonlinear finite element method. Through the analyses of the time history response of the high-rise complex structure to the specified earthquake records, the seismic performances of the structure system under consideration of the rock foundation-sluice structure-reservoir water interaction were well evaluated.

Abstract: The power output characteristics of an electromagnetic energy harvester which uses magnetic levitation to produce the nonlinear vibration were investigated in this paper. A finite element model was developed in the electromagnetic finite element software MAXWELL^®. The results show that the power output of the harvester was strongly influenced by its external loads and structural parameters. The experimental results show that the peak power output of the electromagnetic harvester is 8.2 mW at the resonance of 8.5 Hz under the vibration acceleration of 5m/s². That obtained from the finite element analysis is 8.5 mW at 8.4Hz. The experimental results effectively verify the validity of the finite element modeling.

Abstract: In order to research the stress performance of reinforced concrete beam with different forms of reinforcement around the openings, a numerical simulation on reinforced concrete beam with circle openings is made by using the finite element software. The constitutive relation of concrete offered by the 2010 edition of code for design of concrete structures and the concrete damaged plasticity model is adopted in this article. The damage factor is introduced in the process of modeling, which can reflect the damage of beams with different forms of reinforcement directly and help to reveal the failure mechanism of members. Thus we can propose the optimization of reinforcement method.

Abstract: The free overfall can be used as a simple and accurate device for flow measurement in open channels. In the past, the solution to this problem was found mainly through simplified theoretical expressions or on the basis of experimental data. In this paper, using the meshless smoothed particle hydrodynamics (SPH) method, the free overfall in open channels with even and uneven bottom is investigated. For the even bottom case, subcritical, critical and supercritical flows are simulated. For the uneven bottom case, supercritical flows with different Froude numbers are considered. The free surface profiles are predicted and compared with theoretical and experimental solutions in literature and good agreements are obtained.

Abstract: Parametric design is a kind of concept to build and analyze models by using parameters or variables rather than digits. Models with different specifications can be achieved by changing the parameter values which are associated with the establishment by labeling the size and adding a variety of constraints. To represent the solving system of plane geometry constraints, the concept of floating DOF is applied based on graph theory to represent the state of the constraints system. And through the establishment of the variable passing rules, changes of the parameters can be shown as rational flow effects in graphs so that the system can give a clearly expression and achieve the fast driven effect of the graphics system changes.

Abstract: A numerical model for simulating unsteady flow and sediment transport in the mainstream and its tributaries at the TGR was presented in this paper, and a three-gradation method was applied to solve the flow governing equation. A experience formula was gave for the calculation of the size of groups of different coefficient of saturation recovery based on the analysis, so the traditional calculation method was improved in this paper. The validity of the model was checked with the observed data of the TGR from 2003 to 2011. Good agreement between the calculation and observed data was obtained. The simulation results show that this model could be used to simulate the flow and sediment transport at the TGR.

Abstract: This paper aims to mimic the herd behavior of pedestrian flow, i.e., the tendency towards majority when a congestion occurs, by macroscopic modeling approach. The macroscopic pedestrian simulation model is composed of a mass-conservation equation and a simple model to reflect behavioral characteristics of pedestrians based on a specific traffic situation. Numerical experiments are designed to show some preliminary results, e.g. the beneficial effect of herding on evacuation time in some situations.

Abstract: Taking intake tower of Hydropower Station project for an example, ANSYS is used on the intake tower dynamic, static analysis, to study the distribution of stress and displacement as well as structural stability. The results show that, under load, the deformation and stability of the intake tower to meet the structural design requirements, need to take special measures in the weak parts of the internal forces in the structural design. The results in this paper may be served as the basis of structure design of the intake tower.