Article
Engineering, Civil
S. Negri, G. Tomasini, P. Schito, D. Rocchi
Summary: The train slipstream, which is the velocity of air induced by the train, is a significant aerodynamic effect that directly affects the safety of passengers on the platform and track workers along the railway line. While there have been numerous studies on this phenomenon in open fields, such as the development of specific EU standards like EN 14067-4 and TSI, limited research has been conducted on analyzing the train slipstream in confined spaces like tunnels. This study focuses on studying the effects of train passage on air flow speed through full-scale experimental campaigns, analyzing different train and infrastructure parameters and simulating scenarios of ordinary railway traffic with a stationary train inside the tunnel while another train passes.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Engineering, Civil
Wei Yi, Celia Bertin, Peng Zhou, Jiaqi Mao, Siyang Zhong, Xin Zhang
Summary: In this study, the aerodynamic characteristics of bicycle wheels were investigated using experimental and numerical methods. The results obtained from the experiments and simulations showed good agreement, providing valuable insights into the fluid distribution and force generation in cycling wheels.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Engineering, Civil
Wei-Wei Guo, Bao-Shuo Cai, Fei-Xia Sun, Bao-Ze Ni, Peng-Yu Chen
Summary: An experimental and numerical study was conducted to investigate the aerodynamic characteristics of train vehicles on a truss bridge and the surrounding flow field. The results showed that the pressure coefficients on the surface of the train vehicle were significantly reduced when it moved from a box deck to a truss deck. The flow field inside the truss structure was uneven, with higher wind speeds occurring near the leeward truss panel.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Metallurgy & Metallurgical Engineering
Xiang-fu Tian, Huo-yue Xiang, Xu-li Chen, Yong-le Li
Summary: This study focuses on the dynamic response of a high-speed maglev transit system under crosswind conditions. The aerodynamic characteristics of the maglev vehicle were tested in a wind tunnel, and a PIDA control algorithm was used to adjust the levitation and guidance control system. The effects of wind speeds, vehicle speeds, and track irregularities on the system's dynamic response were analyzed.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Engineering, Civil
Tang-Hong Liu, Lei Wang, Zheng-Wei Chen, Hong-Rui Gao, Wen-Hui Li, Zi-jian Guo, Yu-Tao Xia, Xiao-Shuai Huo, You-Wu Wang
Summary: This study analyzes the effect of pressure pipe length on train surface pressure fluctuations through field tests and determines an appropriate length. It also investigates the aerodynamic performance of trains under crosswind conditions.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Energy & Fuels
Ingrid Neunaber, Frederic Danbon, Antoine Soulier, Dimitri Voisin, Emmanuel Guilmineau, Philippe Delpech, Sebastien Courtine, Claire Taymans, Caroline Braud
Summary: This study combines 2d CFD simulations and experimental investigations to study the rotor blade section of a wind turbine. The results show that there are natural instabilities in the experiments, with local and temporal variations of the flow separation point occurring at angles of attack close to the maximum lift.
Article
Metallurgy & Metallurgical Engineering
Lin-Bo Tang, Xu-Hui He, Lei Yan, Ze Lin
Summary: This paper presents an experimental study on the aerodynamic characteristics of a Fuxing train model passing a bridge-tunnel junction under crosswinds. The experiment utilized a moving model experimental device developed by the Wind Tunnel Laboratory at Central South University, with a wireless pressure measuring device mounted on the train body to monitor aerodynamic pressure. The results indicate significant changes in the train's side force and larger standard deviation of pressure on the windward surface compared to the leeward surface, with similar aerodynamic change patterns on both tracks but greater side force on the windward track due to smaller negative pressure on the windward surface and larger negative pressure on the leeward surface.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Engineering, Aerospace
Xiran Liu, Dan Zhao, Nay Lin Oo
Summary: A better prediction of key aerodynamic parameters of a propeller is necessary to improve the performances of unmanned aerial vehicles (UAVs) in different operating environments. In this work, wind tunnel tests, blade element momentum theory (BEMT), and 3D computational fluid dynamics (CFD) are used to analyze the aerodynamic performances of an APC 1045 multi-rotor propeller. The BEMT model provides accurate estimation at low advance ratios but begins to stall at high advance ratios, while the results from CFD simulations agree well with experiments at all advance ratios. The limitation and advantages of these methods are compared, with the BEMT found to be reliable enough for small-scaled fixed-pitch propellers.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Sport Sciences
Fabien Beaumont, Fabien Bogard, Sebastien Murer, Guillaume Polidori
Summary: The main goal of this study was to compare the aerodynamic optimization level in different rider configurations against a crosswind. The results showed that the spatial management of riders significantly influenced drag and lateral forces, and avoiding being in the guttered position was the best way to save energy in windy races.
JOURNAL OF SCIENCE AND MEDICINE IN SPORT
(2023)
Article
Engineering, Civil
Dipesh Patel, Andrew Garmory, Martin Passmore
Summary: The wake of an isolated, rotating wheel in open-wheel motorsport was investigated using CFD and compared with data from PIV wind tunnel experiments. The results show significant differences in the wake topology between the two methods. The wake consists of incoherent macro-scale eddies and deformed counter-rotating vortices. Analysis also reveals significant transverse and vertical velocity fluctuations in the wake.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Review
Thermodynamics
H. Y. Peng, H. J. Liu, J. H. Yang
Summary: Vertical axis wind turbines (VAWTs) have unique attributes such as exceptional performance in built environments and high packing density in wind farms. This study reviews recent research on the wake aerodynamics of H-rotor VAWTs, presenting mathematical expressions and a classic aerodynamic model for rotor analysis. The wakes of VAWTs are characterized by distinctive features like strong asymmetry and counter-rotating vortical motion, which have led to the development of various wake models for standalone VAWTs or multiple VAWT layouts. Researchers have used a wide range of methods, including wind tunnel testing, PIV tests, field tests, CFD simulations, and theoretical development, to investigate the wake flow fields and vortical structures of VAWTs.
Article
Engineering, Civil
Shaopeng Li, Zhiyang Li, Qingshan Yang, Yi Su, Hongsheng Jiang, Guowei Qian
Summary: The experimental errors caused by the scale effect become more significant when the reproduced turbulence scale is not very large compared to the test model's characteristic dimension. The scale effect can be divided into the 3D effect in the spanwise direction and the distortion effect in the streamwise direction. A theoretical model of the 3D drag admittance is proposed to study the influence mechanism of the scale effect.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Engineering, Civil
Carlos Esteban Araya Reyes, Daniele Rocchi, Gisella Tomasini, Mikel Iraeta Sanchez, Maialen Artano
Summary: Crosswind stability studies have increased since the 90s due to higher speeds and lighter railway vehicles. Initially focused on high-speed trains, recent studies have found that conventional trains at lower speeds are also at risk of overturning in crosswinds. This study analyzed a conventional train designed by CAF to evaluate the impact of different roof and underbody designs on the train's aerodynamic performance. Wind tunnel testing at Politecnico di Milano was conducted on a scaled model to determine the aerodynamic coefficients of different train configurations. The European Standard EN14067-6 procedure was applied to evaluate train stability using time-dependent multibody simulations and the 'Chinese hat' wind time history. Results showed a significant improvement for some configurations, particularly when the roof was closed.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Engineering, Civil
Kytin Kwan, Gregory A. Kopp
Summary: Wind tunnel testing was conducted on structures fabricated using additive manufacturing techniques to determine the impact of edge curvature on aerodynamics. It was found that increasing edge radius alters pressure fields near separation bubbles and conical vortices, exceeding measurement uncertainty when the ratio of edge radius to building height is above approximately 1.3%. This leads to discrepancies in area-averaged pressures, particularly affecting small areas near building edges with surface areas below 2m2 for a low-rise building.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2021)
Article
Engineering, Civil
Erik Josefsson, Teddy Hobeika, Simone Sebben
Summary: The aerodynamics of wheels is a significant factor for the overall performance of a vehicle, and approximately 25% of the total aerodynamic drag comes from the wheels. This study used numerical simulations to investigate the impact of different tires and rims on the aerodynamics of a vehicle, and compared the results to experimental data. It was found that including a wind tunnel model in the simulations improved the prediction of the flow fields.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Engineering, Civil
Zhen Liu, Dan Zhou, David Soper, Guang Chen, Hassan Hemida, Zijian Guo, Xianli Li
Summary: This paper conducts a numerical simulation to analyze the changing slipstream of a maglev train entering a tunnel. The study finds that the fluctuation and magnitude of slipstream inside the tunnel is larger than that on open line, and the maximum turbulent kinetic energy generated inside the tunnel is significant.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT
(2023)
Article
Education & Educational Research
Panagiota Axelithioti, Rachel S. Fisher, Emma J. S. Ferranti, Holly J. Foss, Andrew D. Quinn
Summary: Engineering is crucial for societal progress, but it also contributes to climate change. Engineers have a responsibility to reduce disaster risks and mitigate greenhouse gas emissions. This study examines how higher education prepares engineers to address the climate crisis, focusing on mechanical, civil, and electrical engineering departments. The research finds a lack of emphasis on climate change in course descriptions and learning objectives, highlighting the disconnect between engineering education and the climate reality. The study calls for the integration of climate-conscious content in engineering curricula.
EDUCATION SCIENCES
(2023)
Review
Mechanics
Boyang Chen, Bruno Fraga, Hassan Hemida
Summary: We propose a new modelling tool for the activated sludge process (ASP) that uses large-eddy simulation and multiphase Eulerian-Lagrangian coupling. Our model allows for interaction among the liquid, solid, and gas phases and provides insight into the fluid dynamics during ASP. By considering the dispersed nature of the gas and solid phases and the turbulent mixing in the tank, our three-dimensional model accurately describes the concentrations of different species and the Oxygen exchange. The model was validated against experimental data and used to simulate a realistic scenario in a wastewater plant, showing promising results for optimizing the process.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Thermodynamics
Zheng-Wei Chen, Guang-Zhi Zeng, Syeda Anam Hashmi, Tang-Hong Liu, Lei Zhou, Jie Zhang, Hassan Hemida
Summary: This study aims to investigate the variations in flow fields induced by windbreak transition regions and propose mitigation measures to improve windproof ability. Improved simulation methods were used to simulate the impact on flow structures under different wind angles, and the accuracy of the results was validated with wind tunnel tests. The original windbreak transition region resulted in high peak wind velocities, but mitigation measures such as oblique and circular curve structures were effective in reducing peak wind speeds.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2023)
Article
Engineering, Civil
Hassan Hemida
Summary: This paper provides an overview of computational work in train aerodynamics published in the Journal of Wind Engineering and Industrial Aerodynamics since 1992. It discusses the limitations of early computational power and the use of simplified potential flow solves and 1D codes for train aerodynamics. It then explores the progress in solving fully viscous and turbulent flow for train aerodynamics using RANS models.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Environmental Sciences
Waldemar Schledewitz, Gary Lloyd, Keith Bower, Thomas Choularton, Michael Flynn, Martin Gallagher
Summary: New observations at the Jungfraujoch research station in Switzerland reveal anomalously high concentrations of cloud ice crystals. These concentrations, measured using a high-speed 2D imaging cloud particle spectrometer, exceed expectations for primary and secondary ice production mechanisms. It is suggested that the interaction of turbulent deposition of supercooled droplets on fragile ice-covered snow surfaces creates a strong surface source of ice crystal fragments. Despite low wind speeds, these fragments are re-suspended and continue to grow, contributing significantly to the ice crystal number concentrations.
Article
Energy & Fuels
Ika Kurniawati, Beatriz Beaumont, Ramon Varghese, Danka Kostadinovic, Ivan Sokol, Hassan Hemida, Panagiotis Alevras, Charalampos Baniotopoulos
Summary: This paper investigates the development of a floating artificial sustainable energy island for enhancing the energy independence of islands, with a focus on the case study of Crete. It shows the potential of wind, solar, and ocean wave energy in and around Crete, and proposes a new methodology for selecting the best location of floating offshore platforms. The concept of an innovative floating modular energy island that integrates different renewable energy resources is proposed, and a case study on the energy independency of a big island is provided.
Article
Engineering, Mechanical
Shuan Huo, Hassan Hemida, Mark Sterling
Summary: The process of debris initialisation in tornado-like flow was investigated using Large-eddy Simulation and Lagrangian-particle tracking. The study found that the vertical velocity component is crucial for debris flight initiation, while the tangential and radial velocity components have minimal impact.
JOURNAL OF FLUIDS AND STRUCTURES
(2023)
Article
Engineering, Civil
M. Sterling, S. Huo, C. J. Baker
Summary: This paper investigates the crop fall patterns caused by thunderstorm downburst-like events as a way to understand the flow structure of a downburst. A novel three-dimensional analytical model and a generalized plant model are developed to explore this phenomenon. The study introduces the concept of the lodging front, a dimensionless variable used to quantify the spatial extent of crop failure. Comparison with full-scale data suggests that the model is capable of predicting realistic crop fall patterns and may be used to assess the strength of downbursts in the future.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Engineering, Civil
Zhen Liu, David Soper, Hassan Hemida, Boyang Chen
Summary: Due to the bluff nature of freight trains, traditional 1D numerical modelling techniques struggle to predict pressure wave formation accurately. This paper presents a detailed study on this phenomenon and introduces a redeveloped 1D code capable of simulating bluff freight vehicles. The code accurately predicts the changing effective blockage area caused by flow separation at the train head.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Mechanics
Aleksandra Monka, Bruno Fraga, David Soper, Hassan Hemida
Summary: The fluid dynamics of expiratory events are complex, and understanding how indoor air conditions affect this and the spread of exhaled material is crucial to the prevention of large-scale spread of diseases. Thermal stratification leads to an increased concentration of aerosols in the breathing zone and extends their forward reach.
Article
Environmental Sciences
Maxamillian A. N. Moss, Dagen D. Hughes, Ian Crawford, Martin W. Gallagher, Michael J. Flynn, David O. Topping
Summary: In a comparative study, the capabilities of K-means, hierarchical clustering algorithm (HCA), and GenieClust were examined. K-means and HCA showed consistent cluster profiles and sizes, while GenieClust effectively differentiated various clusters. The use of an autoencoder (AE) enhanced outlier detection for K-means but may have distorted clustering outcomes for HCA. GenieClust, with or without AE, successfully distinguished distinct clusters with greater variability in compositional loadings, identifying more particle types compared to traditional methods.
Article
Environmental Sciences
Ian Crawford, Keith Bower, David Topping, Simone Di Piazza, Dario Massabo, Virginia Vernocchi, Martin Gallagher
Summary: Biological particulate matter (BioPM) is a subset of atmospheric aerosols that is poorly understood but has significant impacts on climate, air quality, and health. This study aimed to develop robust detection methodologies to assess BioPM emissions and their effects. The researchers used real-time bioaerosol spectrometers to monitor BioPM at UK peri-urban and coastal ground sites and developed a classification scheme based on laboratory training data to analyze key species of interest.