scholarly journals Redchyts Evaluation of aerodynamic and thermal loads on the HYPERLOOP capsule fuselage in a partly evacuated tube

2019 ◽  
Vol 4 (123) ◽  
pp. 3-12
Author(s):  
Oleh Borysovych Polovyi ◽  
Dmytro Oleksandrovych Redchyts
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Aerodynamic Drag ◽  
Negative Impact ◽  
Transportation Systems ◽  
Transport Systems ◽  
Aerodynamic Heating ◽  
Thermal Loads ◽  
Important Place ◽  
Evacuated Tube

Aerodynamics occupies an important place in the design of high-speed ground transportation systems. When a vehicle is moving at a speed above 500 km/h under atmospheric pressure, the main energy is spent to overcome the aerodynamic drag. Creating a rarefied atmosphere inside a sealed pipe in order to significantly reduce energy loss is one of the key ideas of the HYPERLOOP project [1].The paper assesses the aerodynamic and thermal loads on the HYPERLOOP capsule fuselage in a partly evacuated tube based on the numerical solution of the Navier-Stokes equations of compressible flow closed by a differential turbulence model [2-4]. Numerical modeling was carried out with the help of the computational fluid dynamics software developed by the scientific researchers of the Institute of Transport Systems and Technologies of the National Academy of Sciences of Ukraine [5].It was shown that even under conditions of low air pressure in a partly evacuated tube the high-speed movement of the HYPERLOOP capsule will be accompanied by the formation of local supersonic zones, shock waves and non-stationary vortex systems. The structure of the flow essentially depends on geometry of the streamlined capsule and the speed of its movement.It was found that the flow structure and the values of aerodynamic dimensionless coefficients weakly depend on the pressure in the partly evacuated tube. Thus, the aerodynamic forces acting on the HYPERLOOP capsule at the same speeds are almost directly proportional to the pressure value in the tube.A certain problem in the design of the HYPERLOOP type high-speed vehicles will be the aerodynamic heating of the capsule fuselage. When the capsule moves at transonic speed the temperature of the outer surface of the capsule will be 60÷900 C. This heat load can have a negative impact on the performance of onboard power supply and control systems, as well as on the ensuring of the passengers’ comfort on the way.

scholarly journals Vehicular Ad hoc Network for Intelligent Transport System: A review

2018 ◽  
Vol 7 (4.36) ◽  
pp. 350
Author(s):  
Mohammed Saad Talib ◽  
Aslinda Hassan ◽  
Burairah Hussin ◽  
Ali Abdul-Jabbar Mohammed ◽  
Ali Abdulhussian Hassan ◽  
...  
Keyword(s):  
Traffic Safety ◽  
Intelligent Transportation Systems ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
High Efficiency ◽  
New Technologies ◽  
Negative Impact ◽  
Transportation Systems ◽  
Transport Systems ◽  
Intelligent Transport System

the numbers of accidents are increasing in an exponential manner with the growing of vehicles numbers on roads in recent years.  This huge number of vehicles increases the traffic congestion rates. Therefore, new technologies are so important to reduce the victims in the roads and improve the traffic safety. The Intelligent Transportation Systems (ITS) represents an emerging technology to improve the road's safety and traffic efficiency. ITS have various safety and not safety applications. Numerous methods are intended to develop the smart transport systems. The crucial form is the Vehicular Ad hoc Networks (VANET). VANET is becoming the most common network in ITS. It confirms human’s safety on streets by dissemination protection messages among vehicles. Optimizing the traffic management operations represent an urgent issue in this era a according to the massive growing in number of circulating vehicles, traffic congestions and road accidents. Street congestions can have significant negative impact on the life quality, passenger's safety, daily activities, economic and environmental for citizens and organizations. Current progresses in communication and computing paradigms fetched the improvement of inclusive intelligent devices equipped with wireless communication capability and high efficiency processors.  

Explicit Formula for Estimating Aerodynamic Drag on Trains Running in Evacuated Tube Transportation

2013 ◽  
Vol 307 ◽  
pp. 156-160
Author(s):  
Yao Ping Zhang
Keyword(s):  
Explicit Formula ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Research Work ◽  
Maglev Train ◽  
Isaac Newton ◽  
Fluent Software ◽  
Evacuated Tube Transportation ◽  
Theory Research ◽  
Evacuated Tube

Because of reducing aerodynamic drag, the maglev train could run at a high-speed in the partial vacuum tube. Scientists of some conutries such as U.S., Swiss and China, have started the research work on high-speed tube trains. In this situation, evacuated tube transportation aerodynamics becomes an important theory research aspect, in which the main study content is how to calculate aerodynamic drag. Based on the explicit formula for estimating aerodynamic drag on moving body in an infinite boundary surroundings put up by Isaac Newton, the evacuated tube surroundings is analyzed and the explicit formula with blockage ratio as an independent variable for estimating aerodynamic drag acted on trains running in the evacuated tube which is a finite space is deduced. With the calculation case, compared with the results came out from the explicit formula got in this paper and the results got by Fluent software, it was found that those results are closed. Thus, the explicit formula created in this paper for conveniently estimating aerodynamic drag based on trains running in evacuated tube transportation is credible.

Divergent Paths, United States and France: Capital Markets, the State, and Differentiation in Transportation Systems, 1840–1940

2009 ◽  
Vol 10 (3) ◽  
pp. 449-497
Author(s):  
Jim Cohen
Keyword(s):  
United States ◽  
World War I ◽  
Capital Markets ◽  
High Speed ◽  
The United States ◽  
Transportation Systems ◽  
The State ◽  
Transport Systems ◽  
World War ◽  
Defining Moment

Why do the United States and France, both capitalist economies that were dominated by private railways in the 19th and early 20th centuries, have very different transport systems today? After World War II France developed 200 mph high speed trains, while railways in the United States declined to near irrelevance. This paper argues that cross-national divergence was caused by private and public actions that structured capitalmarkets and controlled planning. In the United States private financial institutions used capital markets to shape rail development. In France, by way of contrast, the state directly intervened in financial markets and controlled planning. Both systems thrived until World War I. But, then, faced with growing competition from cars, buses and trucks and burdened by excessive debt, they declined towards bankruptcy. The Great Depression became a defining moment as a Socialist-dominated government in France nationalized railways while in the United States, President Roosevelt's New Deal failed to enact policies to ensure the competitive viability of rail in relation to motorized transport. Rarely used archival sources provide much of the evidence for this argument.

Numerical simulation of the flow field over conical, disc and flat spiked body at Mach 6

2010 ◽  
Vol 114 (1154) ◽  
pp. 225-236 ◽  
Author(s):  
R. C. Mehta
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
High Speed ◽  
Blunt Body ◽  
Stokes Equations ◽  
Aerodynamic Drag ◽  
Dynamic Pressure ◽  
Recirculation Region ◽  
Potential Candidate ◽  
Wave Separation

Abstract A forward facing spike attached to a hemispherical body significantly changes its flow field and influences aerodynamic drag and wall heat flux in a high speed flow. The dynamic pressure in the recirculation area is highly reduced and this leads to the decrease in the aerodynamic drag and heat load on the surface. Consequently, the geometry, that is, the length and shape of the spike, has to be simulated in order to obtain a large conical recirculation region in front of the blunt body to get beneficial drag reduction. It is, therefore, a potential candidate for aerodynamic drag reduction for a future high speed vehicle. Axisymmetric compressible laminar Navier-Stokes equations are solved using a finite volume discretisation in conjunction with a multistage Runge-Kutta time stepping scheme. The effect of the spike length and shape, and the spike nose configuration on the reduction of drag is numerically evaluated at Mach 6 at a zero angle-of-attack. The computed density contours agree well with the schlieren images. Additional modification to the tip of the spike to get different types of flow field such as the formation of a shock wave, separation area and reattachment point are examined. The spike geometries include the conical spike, the flat-disk spike and the hemispherical disk spike of different length to diameter ratios attached to the blunt body.

scholarly journals Analytical Solution of Heat Conduction from Turbulence with an Isotropic Example

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Steven A. E. Miller
Keyword(s):  
Power Spectrum ◽  
Heat Equation ◽  
Turbulent Flows ◽  
High Speed ◽  
Isotropic Turbulence ◽  
Stokes Equations ◽  
Single Equation ◽  
Aerodynamic Heating ◽  
Acoustic Analogy ◽  
Chaotic Motions

Aerodynamic heating due to turbulence significantly affects the operation of high-speed vehicles and the entrainment of fluid by turbulent plumes. In this paper, the heat generated and convected by fluid turbulence is examined by rearranging the Navier-Stokes equations into a single equation for the fluctuating dependent variables external to unsteady chaotic motions. This equation is similar to the nonhomogeneous heat equation where sources are terms resulting from this rearrangement. Mean and fluctuating quantities are introduced, and under certain circumstances, a heat equation for the fluctuating density results with corresponding mean and fluctuating source terms. The resultant equation is similar to Lighthill’s acoustic analogy and is a “heat analogy.” A solution is obtained with the use of Green’s function as long as the observer is located outside the region of chaotic motion. Predictions for the power spectrum are shown for high Reynolds number isotropic turbulence. The power spectrum decays as the inverse of the wavenumber of the turbulent velocity fluctuations. The developed theory can easily be applied to other turbulent flows if the statistics of unsteady motion can be estimated.

scholarly journals Optical Camera Communication Performance Evaluation: Review

2020 ◽  
pp. 42-49
Keyword(s):  
Motion Detection ◽  
Intelligent Transportation Systems ◽  
High Speed ◽  
Indoor Localization ◽  
Image Sensor ◽  
Transportation Systems ◽  
Transport Systems ◽  
Communication Performance ◽  
Signal Processing Methods ◽  
Optical Camera Communication

Recently, optical wireless communication (OWC) technologies focused on a camera or an image sensor receiver have drawn specific attention in areas like the internet, indoor localization, motion detection, and intelligent transportation systems. Besides, panorama sensors are the subject of communications from picture sensors as receptors as the high-speed OWC strategy do not need any change to the existing network, so the difficulty and expense of deployment are very limited. So in this paper, a detailed review of the techniques of optical camera communication (OCC)has been presented. In addition to their function of localizing, tracking and recording motion. Through addressing several facets of OCC and their different implementations, this study varies from the latest literature on this topic. The first section of the current article is on standardization, Path classification, modulation, scripting, synchronization, and signal processing methods for OCC networks whereas the second section of the research discusses OCC-based localization, navigation, motion detection, and smart transport systems literature .Finally , OCC's problems and potential work directions have been addressed in the final section of the research.

Numerical Investigation of Aerodynamic Drag on Vacuum Tube High Speed Train

2013 ◽  
Author(s):  
Sreeja Bibin ◽  
Sujay Kumar Mukherjea
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Aerodynamic Drag ◽  
Vacuum Pressure ◽  
Navier Stokes ◽  
Optimum Shape ◽  
Blockage Ratio ◽  
High Speed Train ◽  
Vacuum Tube ◽  
Turbulent Modeling

This work involves numerical simulations based on finite volume method to study the effects of different factors on the aerodynamic drag on a vacuum tube train running at subsonic and transonic speeds in a partially vacuum tunnel. Investigation includes the study of the effects of the shapes of head, tail, vacuum pressure and also blockage ratio of the tunnel on aerodynamic drag on a high speed train. The simulation is performed by using fluent software. Two dimensional, axisymmetric, compressible Navier-Stokes equations were solved by using k-ε turbulent modeling. Five different blockage ratios at five different speeds of the train have been considered. The simulated results show that, the blockage ratio and different working vacuum pressure significantly affects the aerodynamic drag of the train in a tunnel. Investigations with respect to different shapes of the head as well as that of the tail indicate the optimum shape for minimum drag.

A Comprehensive Study on Intelligent Transportation Systems

2018 ◽  
Vol 4 (10) ◽  
pp. 10
Author(s):  
Ankur Mishra ◽  
Aayushi Priya
Keyword(s):  
Intelligent Transportation Systems ◽  
Traffic Congestion ◽  
Transportation Systems ◽  
Environmental Conservation ◽  
Integrated System ◽  
Transport Systems ◽  
Transport Sector ◽  
Intelligent Transport System ◽  
Intelligent Transport ◽  
Transportation Sector

Transportation or transport sector is a legal source to take or carry things from one place to another. With the passage of time, transportation faces many issues like high accidents rate, traffic congestion, traffic & carbon emissions air pollution, etc. In some cases, transportation sector faced alleviating the brutality of crash related injuries in accident. Due to such complexity, researchers integrate virtual technologies with transportation which known as Intelligent Transport System. Intelligent Transport Systems (ITS) provide transport solutions by utilizing state-of-the-art information and telecommunications technologies. It is an integrated system of people, roads and vehicles, designed to significantly contribute to improve road safety, efficiency and comfort, as well as environmental conservation through realization of smoother traffic by relieving traffic congestion. This paper aims to elucidate various aspects of ITS - it's need, the various user applications, technologies utilized and concludes by emphasizing the case study of IBM ITS.

scholarly journals CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3934
Author(s):  
Federico Lluesma-Rodríguez ◽  
Temoatzin González ◽  
Sergio Hoyas
Keyword(s):  
Shock Waves ◽  
Power Consumption ◽  
High Speed ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Flow Behavior ◽  
Critical Conditions ◽  
Vehicle Speed ◽  
Blockage Ratio ◽  
The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

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