On computational fluid dynamics modelling of crosswind effects for high-speed rolling stock

2003 ◽  
Vol 217 (3) ◽  
pp. 203-226 ◽  
Author(s):  
B Diedrichs
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Flow Simulation ◽  
Sensitivity Study ◽  
Simulation Software ◽  
Rolling Stock ◽  
High Speed Train ◽  
Crosswind Stability ◽  
Deutsche Bahn

This work addresses crosswind stability exemplified for the German Railway Deutsche Bahn AG high-speed train ICE 2. The scope of the work is to describe the flow by means of computational fluid dynamics past the leading two cars of the train for yaw angles in the range 12.2–40.0°. Three track formations are utilized. The basic results are the set of independent aerodynamic coefficients for the lead and subsequent cars. The results are to some extent compared with experimental data for ICE 2 and also with data obtained for the Swedish high-speed train X2000. A numerical sensitivity study is undertaken to quantify differences in the above results dependent on the grid density and quality, turbulence model, numerical scheme, location of inlet and outlet boundaries, turbulence intensity and flow simulation software.

scholarly journals CFD analysis on the aerodynamics characteristics of Jakarta-Bandung high speed train

2018 ◽  
Vol 159 ◽  
pp. 02038 ◽  
Author(s):  
Tony Utomo ◽  
Berkah Fajar ◽  
Hendry Arpriyanto
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
High Speed ◽  
Computational Domain ◽  
Cfd Analysis ◽  
High Speed Train ◽  
Pressure Area ◽  
Train Speed ◽  
Simulation Results

In this study, the aerodynamics characteristics of HST type CRH380A which is planned to be operated on the new railway of Jakarta-Bandung are analysed using Computational Fluid Dynamics. The speed of the train in this simulation was varied from 100 km/h to a maximum designed speed of 350 km/h with the increment of 30 km/h. The train was modelled in 3D computational domain with more than 1.7 million cells. The turbulence model employed in this study was standard k-ω. The simulation results show that the drag coefficient (CD) is slightly decrease by the increase of speed. At the speed of 100 km/h the CD is 0.216 and decrease to 0.188 at the speed of 350 km/h. The high pressure area is located at the nose of the train. The pressure acting on this location is increase with the increase of the train speed.

scholarly journals The NPARC Alliance

1995 ◽  
Author(s):  
Jay A. Cossentine ◽  
Jere J. Matty ◽  
Robert J. Shaw
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Simulation ◽  
Simulation Software ◽  
Research Center ◽  
Nasa Lewis Research ◽  
Academic Institutions ◽  
Engineering Development ◽  
Computational Fluid Dynamics Cfd ◽  
Development Center

The Arnold Engineering Development Center (AEDC) and the NASA Lewis Research Center (LeRC) have formed a government alliance aimed at establishing and supporting a national, application-oriented computational fluid dynamics (CFD) capability, centered around the NPARC flow simulation software. The Alliance is supported by and responsive to an association made up of more that 100 active users at over 60 government, industry, and academic institutions. This paper discusses the history, structure, and philosophy of the NPARC Alliance.

Effect of the inter-car gap length on the aerodynamic characteristics of a high-speed train

2018 ◽  
Vol 233 (4) ◽  
pp. 448-465 ◽  
Author(s):  
Tian Li ◽  
Ming Li ◽  
Zheng Wang ◽  
Jiye Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Drag Force ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Aerodynamic Characteristics ◽  
High Speed Train ◽  
Wind Tunnel Experiments ◽  
The Impact

In wind tunnel experiments, the inter-car gaps are designed in such a way as to separate the force measurements for each car and prevent the interference between cars during tests. Moreover, the inter-car gap has a significant effect on the aerodynamic drag of a train. In order to guide the design of the inter-car gaps between cars in wind tunnel experiments, the impact of the inter-car gap length on the aerodynamic characteristics of a 1/8th scale high-speed train is investigated using computational fluid dynamics. The shear stress transport k-ω model is used to simulate the flow around a high-speed train. The aerodynamic characteristics of the train with 10 different inter-car gap lengths are numerically simulated and compared. The 10 different inter-car gap lengths are 5, 8, 10, 15, 20, 30, 40, 50, 60, and 80 mm. Results indicate that the aerodynamic drag coefficients obtained using computational fluid dynamics fit the experimental data well. Rapid pressure variations appear in the upper and lower parts of the inter-car gaps. With the increase of the inter-car gap length, the drag force coefficient of the head car gradually increases. The total drag force coefficients of the trains with the inter-car gap length less than 10 mm are practically equal to those of the trains without inter-car gaps. Therefore, it can be concluded from the present study that 10 mm is recommended as the inter-car gap length for the 1/8th scale high-speed train models in wind tunnel experiments.

scholarly journals A comparative study of methods to simulate aerodynamic flow beneath a high-speed train

2017 ◽  
Vol 232 (5) ◽  
pp. 1464-1482 ◽  
Author(s):  
David Soper ◽  
Dominic Flynn ◽  
Chris Baker ◽  
Adam Jackson ◽  
Hassan Hemida
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Simulations ◽  
High Speed ◽  
Experimental Studies ◽  
Model Tests ◽  
Full Scale ◽  
High Speed Train ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

The introduction of dedicated high-speed railway lines around the world has led to issues associated with running trains at very high speeds. Aerodynamic effects proportionally increase with train speed squared; consequently, at higher speeds aerodynamic effects will be significantly greater than those of trains travelling at lower speeds. On ballasted track beds, the phenomenon in which ballast particles become airborne during the passage of a high-speed train has led to the need for understanding the processes involved in train and track interaction (both aerodynamical and geotechnical). The difficulty in making full-scale aerodynamic measurements beneath a high-speed train has created the requirement to be able to accurately simulate these complex aerodynamic flows at the model scale. In this study, the results of moving-model tests and numerical simulations were analysed to determine the performance of each method for simulating the aerodynamic flow underneath a high-speed train. Validation was provided for both cases by juxtaposing the results against those from full-scale measurements. The moving-model tests and numerical simulations were performed at the 1/25th scale. Horizontal velocities from the moving-model tests and computational fluid dynamics simulations were mostly comparable except those obtained close to the ballast. In this region, multi-hole aerodynamic probes were unable to accurately measure velocities. The numerical simulations were able to resolve the flow to much smaller turbulent scales than could be measured in the experiments and showed an overshoot in peak velocity magnitudes. Pressure and velocity magnitudes were found to be greater in the numerical simulations than in the experimental tests. This is thought to be due to the influence of ballast stones in the experimental studies allowing the flow to diffuse through them, whereas in the computational fluid dynamics simulations, the flow stagnated on a smooth non-porous surface. Additional validation of standard deviations and turbulence intensities found good agreement between the experimental data but an overshoot in the numerical simulations. Both moving model and computational fluid dynamics techniques were shown to be able to replicate the flow development beneath a high-speed train. These techniques could therefore be used as a method to model underbody flow with a view to train homologation.

Durability Analysis of the Reduction Gear for High Speed Train Considering Driving Histories

2012 ◽  
Vol 586 ◽  
pp. 269-273
Author(s):  
Chul Su Kim ◽  
Gil Hyun Kang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Element Model ◽  
Rolling Stock ◽  
Reduction Gear ◽  
High Speed Train ◽  
Analysis Software ◽  
Tractive Effort ◽  
Durability Analysis ◽  
The Finite Element Model

To assure the safety of the power bogies for train, it is important to perform the durability analysis of reduction gear considering a variation of velocity and traction motor capability. In this study, two types of applied load histories were constructed from driving histories considering the tractive effort and the train running curves by using dynamic analysis software (MSC.ADAMS). Moreover, this study was performed by evaluating fatigue damage of the reduction gears for rolling stock using durability analysis software (MSC.FATIGUE). The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the gears. The results showed that the fatigue life of the reduction gear would decrease with an increasing numbers of stops at station.

scholarly journals Aerodynamic analysis of uphill drafting in cycling

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Scientific Literature ◽  
Sensitivity Analyses ◽  
Air Resistance ◽  
Wind Tunnel Measurements ◽  
Aerodynamic Effect ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

Slam load estimation for high-speed catamarans in irregular head seas by full-scale computational fluid dynamics

2021 ◽  
Vol 234 ◽  
pp. 109160
Author(s):  
Islam Almallah ◽  
Jason Ali-Lavroff ◽  
Damien S. Holloway ◽  
Michael R. Davis
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Full Scale ◽  
Load Estimation
Sign in / Sign up

Export Citation Format

Share Document