Papers by Keyword: Pressure Distribution

Abstract: Based on the subjective questionnaire data, anthropometric data, and the pressure distribution data, the relationship between pressure distribution and wheelchair static comfort is studied. Subjective evaluation of comfort is collected through subjective questionnaires; experimenter pressure distribution data is extracted through pressure distribution experiment. Using anthropometric data and pressure distribution data as input, and integrated comfort as output, wheelchair comfort network prediction model is established based on artificial neural network, wheelchair ride comfort can be predicted through pressure distribution. This method converts the subjective evaluation to objective measurement.

Abstract: Airfoils have become a combined aspect of human flight as it has evolved over the last century. As the design of each airfoil determines many aspects of its use in the real world, all significant characteristics must be analyzed prior to implementation. The aerodynamic effects of pressure, drag, lift, and pitching moment are used to evaluate the behavior of the airfoil. The airfoil shape is expressed analytically as a function of some design parameters. The NACA 0012 and NACA 2412 are used with design parameters that control the camber and the thickness of the airfoil. Singularity method is the way to determine velocity distribution and pressure distribution of the airfoils. In order to apply it to the potential flow, Kutta condition and kinematic flow condition must be satisfied. It is expedient to treat a very thin profile. In this work, three vertical blades wind car, and directly connected to wheels by using of various kinds of links, and gears are used to convert the wind energy to mechanical energy to overcome the load that rotates the main shaft. The purpose of this work is to determine the torque, lift and drag forces of the different types of NACA airfoils that can be used in electric power generating or running our wind car. This was done by calculating of pressure distribution over the upper and lower surface of the airfoil to calculate the velocity distribution, lift and drag coefficient.

Abstract: Numerical simulations were carried out to investigate the air flow and pressure distributions beneath high speed trains, based on the three-dimensional Reynolds-averaged Navier-Stokes equations with the SST k-ω two-equation turbulence model. The simulation scenarios were of the high speed train, the CRH2, running in the open air at four different speeds: 200km/h, 250km/h, 300km/h and 350km/h. The results show that, the highest area of pressure is located at the front underbody part of the train whist the pressure for rest of the train is relatively small. Increasing speed does not visibly increase the pressure coefficient, indicating that the pressure increases with the square of the operational speed.

Abstract: According to the variation of the flow parameters of the flow velocity v, outlet pressure P0 and fluid density ρ by using the FLUENT software, the influencing regularity of the distribution of the inner surface pressure in elbow pipe was analyzed. Based on the study, the pressure computational formula for 90 degree elbow pipe on the characteristic section α=45° was built. The research conclusion lays the groundwork for strength check and structural design of the elbow pipe.

Abstract: The particle motion in fluid has attracted much attention in material engineering concerned the particle effects such as the debris in lubrication and the particles deposition in material processing. By taking the hydrodynamic effect into account, the pressure distribution around particles in fluid in confined wedge space is analyzed. The influences of the particle position, particle shape and its velocity on the pressure distribution are also investigated. Results show that in confined wedge space, the fluid pressure around the particle in the side near the upper slope plate is larger than that in another side, which may make the particle move downwards. And the pressure discrepancy between both sides of the particle increases with the particle shape, the particle velocity and the particle coordinates in both directions of x and z. These special phenomenons may be used in structured surfaces fabrication based on particle deposition by constructing special fluid field.

Abstract: Radial fatigue life is an important index of automotive wheel. Traditional analysis method neglected the force on flange and confused stable inflation load with dynamic radial load. In this study, a 3D finite element (FE) analysis was executed simulating the inflation and radial press process. Different contact and modeling techniques were adopted to improve the convergence and accuracy. Stable and dynamic pressure on flange and bead seat were distinguished and approximated with different functions. Finally, experiments and comparison were made to ensure the reliability of the method.

Abstract: Tipping-over and slipping, which are related to zero moment point (ZMP) and frictional constraint respectively, are the most two common instability forms of biped robotic walking. Conventional criterion of stability is not sufficient in some cases, since it neglects frictional constraint or considers only translational friction. The goal of this article is to fully address frictional constraints in biped walking and develop corresponding stability criteria. Frictional constraints for biped locomotion are first analyzed and the method to obtain the closed-form solutions of the frictional force and moment for a biped robot with rectangular or circular feet is then presented. The maximum frictional force and moment are calculated in the case of ZMP at the center of contact area. Experiments are conducted to verify the effectiveness of our stability analysis.

Abstract: This paper numerically calculates the pressure distributions of a rudder of a ship for structure strength design. The sections profile of the rudder is NACA0020 airfoil. The viscous flow is simulated by FLUENT commercial software, while the model and mesh is generated by GAMBIT software. A 2D viscous flow around a NACA0020 airfoil is calculated firstly. Some notices are given here about the magnitude of computing domain, the density distribution and the numbers of grid nodes on the airfoil surface in order to gain better results. Then, based on these experiences, the viscous flow around a 3D rudder is simulated. The calculated pressure coefficients on the rudder’s section are compared with the experiment results and BEM results of the potential theory. At the attack angles and , the three results agree well with each other. However, when the attack angle is , the viscous results from FLUENT give better agreement with the experiment results than the BEM results. This conclusion confirms that the viscosity effect is great in the case of large attack angles.

Abstract: The experiment is carried out in a 13-meter-high circulating fluidized bed(CFB) to investigate gas-solid two-phase flow by pressure sensor. The axial pressure and pressure fluctuation are measured in different solid mass fluxes. With the solid mass flux increasing, pressure gradually increases, and pressure gradually decreases along the riser upwards. The characteristic of pressure fluctuation in the riser is analyzed, which indicates that pressure fluctuation in the riser originates from the inlet. The intensity of the pressure fluctuation decreases along the riser upwards. This pressure fluctuation is composed of two types: one is of low frequency and high amplitude, which is resulted from unstable feeding to the riser and keeps coherent along the axial direction. And the other is of high frequency and low amplitude, which is the result of a variety of factors, such as cluster movement, gas-solid interaction and gas velocity fluctuation.

Abstract: The existing “structure load code” did not give wind load shape coeeficient of rhombic plane and saddle-shaped roof .On this issue, numerical wind tunnel method has significant advantages such as low cost,fasting,collecting more comprehensive results.Using information of CFD and the software of FLUENT, using RNG - turbulence model, simulating a landform rhombic plane, the paper had numerical simulation of average wind pressure coefficient for rhombic plane and saddle-shaped roof building. It focused the effect on the numerical simulation for bending-span ratio. Finally it provided reference for reasonably determining the average wind pressure coefficient of rhombic plane and saddle-shaped roof building.