Aerodynamic Simulation of the Air Flow beneath the High Speed Train

2012 ◽  
Vol 253-255 ◽  
pp. 2035-2040
Author(s):  
Ye Bo Liu ◽  
Zhi Ming Liu
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Air Flow ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
High Speed Trains

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.

Wind-Induced Response of ADSS during the Passage of High-Speed Train

2014 ◽  
Vol 590 ◽  
pp. 69-73
Author(s):  
Yu Wang ◽  
Qiang Gao ◽  
Hai Lin Wang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Induced Response ◽  
Wind Flow ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
High Speed Trains

In this paper, the wind-induced response of the ADSS is analyzed when the high-speed trains pass by. The wind flow field of the high-speed train is simulated based on the three-dimensional Reynolds-averaged Navier–Stokes equations, combined with the k-ε turbulence model. The result is shown that the wind load acting on the ADSS is quite low and the stress of the line clamp increases a little.

A Study of Aerodynamic Effects of High-Speed Trains through Tunnels

2011 ◽  
Vol 94-96 ◽  
pp. 1663-1667
Author(s):  
Jing Zhao ◽  
Ren Xian Li
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Geometry Model ◽  
Flow Geometry ◽  
High Speed Trains ◽  
Set Up ◽  
Numerical Calculation Method

In this paper, the aerodynamic effects of high-speed train passing in tunnels are investigated in numerical calculation method of hydromechanics. According to the actual situation of flow filed when the train through the tunnel, the flow geometry model is set up. The flow problem is described by Navier-Stokes equations of unsteady viscous compressible fluid and k-e two equations turbulent model. Thereby the aerodynamic effects of the train through the tunnel are analyzed comprehensively. The changes of the air pressure in tunnel caused by high-speed train entering into the tunnel are mainly analyzed. In addition, the mechanical characteristics of carriages when two train in the tunnel passing through each other are analyzed.

Simulation of the subsonic flow in a high-speed centrifugal compressor impeller by the pressure-based method

1998 ◽  
Vol 212 (4) ◽  
pp. 269-287 ◽  
Author(s):  
Y Wang ◽  
S Komori
Keyword(s):  
High Speed ◽  
Compressible Flows ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Navier Stokes Equations ◽  
Compressor Impeller ◽  
Collocated Grid

A pressure-based finite volume procedure developed previously for incompressible flows is extended to predict the three-dimensional compressible flow within a centrifugal impeller. In this procedure, the general curvilinear coordinate system is used and the collocated grid arrangement is adopted. Mass-averaging is used to close the instantaneous Navier-Stokes equations. The covariant velocity components are used as the main variables for the momentum equations, making the pressure-velocity coupling easier. The procedure is successfully applied to predict various compressible flows from subsonic to supersonic. With the aid of the k-ɛ turbulence model, the flow details within a centrifugal impeller are obtained using the present procedure. Predicted distributions of the meridional velocity and the static pressure are reasonable. Calculated radial velocities and flow angles are favourably compared with the measurements at the exit of the impeller.

Numerical Study on Impeller Performance of Mini Hydro Turbine

2015 ◽  
Vol 772 ◽  
pp. 552-555 ◽  
Author(s):  
Kyu Han Kim ◽  
Joni Cahyono
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Hydro Turbine ◽  
Pressure Distributions ◽  
Power Outputs

The aim of this paper is to numerically explore the feasibility of designing a Mini-Hydro turbine. The interest for this kind of horizontal axis turbine relies on its versatility. In the present study, the numerical solution of the discredited three-dimensional, incompressible Navier-Stokes equations over an unstructured grid is accomplished with an ANSYS program. In this study, a mini hydro turbine (3kW) has been considered for utilization of horizontal axis impeller. The turbine performance and flow behavior have been evaluated by means of numerical simulations. Moreover, the performance of the impeller varied in the pressure distribution, torque, rotational speed and power generated by the different number of blades and angles. The results trends are similar between the highest pressure distributions at the impeller also produced highest power outputs on 6 numbers of blades at impeller. The model has been validated, comparing numerical results with available experimental data.

The Interaction Between the Impeller and Casing in a Small-Size Turbo-Compressor

2002 ◽  
Author(s):  
D.-W. Kim ◽  
Youn J. Kim
Keyword(s):  
Static Pressure ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reference Method ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
Loss Coefficients ◽  
Compressible Turbulent Flow ◽  
Turbo Compressor

The effects of casing shape on the performance and the interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are performed for the circular casing. Comparison of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.

A Finite Element Analysis of the Navier-Stokes Equations Applied to High Speed Thin Film Lubrication

1987 ◽  
Vol 109 (1) ◽  
pp. 71-76 ◽  
Author(s):  
J. O. Medwell ◽  
D. T. Gethin ◽  
C. Taylor
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
The Finite Element Method ◽  
Thin Film Lubrication ◽  
Element Analysis ◽  
Navier Stokes Equations ◽  
Film Lubrication

The performance of a cylindrical bore bearing fed by two axial grooves orthogonal to the load line is analyzed by solving the Navier-Stokes equations using the finite element method. This produces detailed information about the three-dimensional velocity and pressure field within the hydrodynamic film. It is also shown that the method may be applied to long bearing geometries where recirculatory flows occur and in which the governing equations are elliptic. As expected the analysis confirms that lubricant inertia does not affect bearing performance significantly.

Three Dimensional Simulation of Bore Flow Using SPH

2010 ◽  
Author(s):  
Huaxing Liu ◽  
Soon Keat Tan ◽  
Jing Li ◽  
Xikun Wang
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Smooth Particle Hydrodynamic ◽  
Navier Stokes ◽  
Initial Water ◽  
Navier Stokes Equations ◽  
Sph Model ◽  
Complex Fluid ◽  
Dimensional Simulation

Tidal bore is a fascinating and powerful hydraulic phenomenon. In this paper, the tidal bore’s process is studied using 3D Smooth Particle Hydrodynamic (SPH) model. The Lagrangian nature of SPH suits well to the modeling of the complex fluid flow phenomenon. In the SPH method, the Navier-Stokes equations are discretized with fluid particles in the Lagrangine sense. Boundary conditions, including both no slip wall and bottom wall, are implemented using dynamic boundary particles. Using SPH, the bore’s generation together with its traverse along the channel are presented, including the description of flow field and bore’s configuration. Different types of bores’ behavior are investigated. It is observed that there is a splash of water surge up the wall and the front of the bore becomes a breaker wave when the initial water column travels at high speed. The velocity field and bore heights at different locations are visualized and discussed as well.

Research of Train Wind Characteristics in High-Speed Railway Tunnel

2014 ◽  
Vol 919-921 ◽  
pp. 865-868 ◽  
Author(s):  
Rui Zhen Fei ◽  
Li Min Peng ◽  
Wei Chao Yang ◽  
Wei Guang Yan
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Time History ◽  
Space Distribution ◽  
Navier Stokes ◽  
Railway Tunnel ◽  
High Speed Railway ◽  
Navier Stokes Equations ◽  
Tunnel Cross Section

According to the 100㎡ high-speed tunnel cross-section which is generally used in high-speed railway of China, this paper develops a tunnel-air-train simulation model, based on the three-dimensional incompressible Navier-Stokes equations and the standard k-e turbulence model. Time-history variation rules and space distribution characteristics of train wind are studied respectively. The results show that: train wind is complex three-dimensional flow changing with time and space, air at the front of train flows away from the train head, while air at the rear of train flows to the train tail.

Simulation of Three-Dimensional Shear Flow Around a Nozzle-Afterbody at High Speeds

1992 ◽  
Vol 114 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Oktay Baysal ◽  
Wendy B. Hoffman
Keyword(s):  
Shear Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Surface Flow ◽  
Navier Stokes ◽  
Turbulent Shear ◽  
Duct Flow ◽  
Navier Stokes Equations ◽  
Eddy Viscosity Model ◽  
Pressure Distributions

Turbulent shear flows at supersonic and hypersonic speeds around a nozzle-afterbody are simulated. The three-dimensional, Reynolds-averaged Navier-Stokes equations are solved by a finite-volume and implicit method. The convective and the pressure terms are differenced by an upwind-biased algorithm. The effect of turbulence is incorporated by a modified Baldwin-Lomax eddy viscosity model. The success of the standard Baldwin-Lomax model for this flow type is shown by comparing it to a laminar case. These modifications made to the model are also shown to improve flow prediction when compared to the standard Baldwin-Lomax model. These modifications to the model reflect the effects of high compressibility, multiple walls, vortices near walls, and turbulent memory effects in the shear layer. This numerically simulated complex flowfield includes a supersonic duct flow, a hypersonic flow over an external double corner, a flow through a non-axisymmetric, internal-external nozzle, and a three-dimensional shear layer. The specific application is for the flow around the nozzle-afterbody of a generic hypersonic vehicle powered by a scramjet engine. The computed pressure distributions compared favorably with the experimentally obtained surface and off-surface flow surveys.

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