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Abstract With the rapid growth of automobile ownership, traffic congestion has become a major concern at intersections. In order to alleviate the blockage of intersection traffic flow caused by signals, reduce the length of vehicle congestion and waiting time, and for improving the intersection access efficiency, therefore, this article proposes a vehicle speed guidance strategy based on the intersection signal change by combining the vehicle–road cooperative technology. The randomness of vehicle traveling speed in the road is being considered. According to the vehicle traveling speed, a speed guidance model is established under different conditions.

Abstract The ground vibration test (GVT) is an important phase in a new aircraft development program, or the structural modification of a certified aircraft, to experimentally determine the structural vibrational modes of the aircraft and their modal parameters. These modal parameters are used to validate and correlate the dynamic finite element model of the aircraft to predict potential structural instabilities (such as flutter), assessing the significance of modifications to research vehicles by comparing the modal data before and after the modification and helping to resolve in-flight anomalies. Due to the high cost and the extensive preparations of such tests, a new method of vibration testing called the taxi vibration test (TVT) rooted in operational modal analysis (OMA) was recently proposed and investigated as an alternative method to conventional GVT.

Abstract Vehicle-to-infrastructure (V2I) connectivity technology presents the opportunity for vehicles to perform autonomous longitudinal control to navigate safely and efficiently through sequences of V2I-enabled intersections, known as connected corridors. Existing research has proposed several control systems to navigate these corridors while minimizing energy consumption and travel time. This article analyzes and compares the simulated performance of three different autonomous navigation systems in connected corridors: a V2I-informed constant acceleration kinematic controller (V2I-K), a V2I-informed model predictive controller (V2I-MPC), and a V2I-informed reinforcement learning (V2I-RL) agent. A rules-based controller that does not use V2I information is implemented to simulate a human driver and is used as a baseline. The performance metrics analyzed are net energy consumption, travel time, and root-mean-square (RMS) acceleration.

Abstract The cooperative platoon of multiple trucks with definite proximity has the potential to enhance traffic safety, improve roadway capacity, and reduce fuel consumption of the platoon. To investigate the truck platooning performance in a real-world environment, two Peterbilt class-8 trucks equipped with cooperative truck platooning systems (CTPS) were deployed to conduct the first-of-its-kind on-road commercial trial in Canada. A total of 41 CTPS trips were carried out on Alberta Highway 2 between Calgary and Edmonton during the winter season in 2022, 25 of which were platooning trips with 3 to 5 sec time gaps. The platooning trips were performed at ambient temperatures from −24 to 8°C, and the total truck weights ranged from 16 to 39 tons. The experimental results show that the average time gap error was 0.8 sec for all the platooning trips, and the trips with the commanded time gap of 5 sec generally had the highest variations.

Abstract The broadband aeroacoustics of a side mirror is investigated with a stochastic noise source method and compared to scale-resolving simulations. The setup based on an already existing work includes two geometrical variants with a plain series side mirror and a modified mirror with a forward-facing step mounted on the inner side. The aeroacoustic near- and farfield is computed by a hydrodynamic–acoustic splitting approach by means of a perturbed convective wave equation. Aeroacoustic source terms are computed by the Fast Random Particle-Mesh method, a stochastic noise source method modeling velocity fluctuations in time domain based on time-averaged turbulence statistics. Three RANS models are used to provide input data for the Fast Random Particle-Mesh method with fundamental differences in local flow phenomena.

Abstract In recent years, the number of electric vehicles (EVs) has grown rapidly, as well as public interest in them. However, the lack of sufficient range is one of the most common complaints about these vehicles, which is particularly problematic for people with long daily commutes. Thus, this article proposed a solution to this problem by installing micro wind turbines (MWTs) on EVs as a range extender. The turbines will generate electricity by converting the kinetic energy of the air flowing through the MWT into mechanical energy, which can have a reasonable effect on the vehicle aerodynamics. The article uses mathematical modelling and numerical analysis. Regarding the modelling, a detailed EV model in MATLAB/SIMULINK was developed to analyze the EV performance using various driving cycles in real time.

Abstract Vehicular automation in the form of a connected and automated vehicle platoon is demanding as it aims to increase traffic flow and driver safety. Controlling a vehicle platoon on a curved path is challenging, and most solutions in the existing literature demonstrate platooning on a straight path or curved paths at constant speeds. This article proposes an algorithmic solution with leader-following (LF) communication topology and constant distance (CD) spacing for platooning homogeneous position-controlled vehicles (PCVs) on a curved path, with each vehicle capable of cornering at variable speeds. The lead vehicle communicates its reference position and orientation to all the follower vehicles. A follower vehicle stores this information as a virtual trail of the lead vehicle for a specific period. An algorithm uses this trail to find the follower vehicle’s reference path by solving an optimization problem.

Abstract In the pursuit of advancing autonomous vehicles (AVs), data-driven algorithms have become pivotal in replacing human perception and decision-making. While deep neural networks (DNNs) hold promise for perception tasks, the potential for catastrophic consequences due to algorithmic flaws is concerning. A well-known incident in 2016, involving a Tesla autopilot misidentifying a white truck as a cloud, underscores the risks and security vulnerabilities. In this article, we present a novel threat model and risk assessment (TARA) analysis on AV data storage, delving into potential threats and damage scenarios. Specifically, we focus on DNN parameter manipulation attacks, evaluating their impact on three distinct algorithms for traffic sign classification and lane assist.

Abstract Since the steady-state computational fluid dynamics (CFD) Reynolds-averaged Navier–Stokes (RANS) turbulence models offer low-cost and sensible accuracy, they are frequently utilized for bluff bodies’ external aerodynamics investigations (e.g., upwind, crosswind, and shape optimization). However, no firm certainty is made regarding the best model in terms of accuracy and cost. Based on cost and accuracy aspects, four RANS turbulence models were studied, which are Spalart–Allmaras, realizable k-ε, RNG k-ε, and SST k-ω. Ahmed body with a 25° slant angle benchmark case was introduced for this investigation. Two grids were generated to satisfy the near-wall treatment of each turbulence model. All grid settings were proposed and discussed in detail. Fluid-structure analysis was performed on five different planes.

Abstract In order to promote the actual application of the vehicular platoon, this study investigates the effect of the specific platoon configurations including predecessor following (PF), predecessor–leader following (PLF), and bidirectional following (BD), on the anti-disturbing performance from the linear to nonlinear perspective. First, based on the method of sensitivity of error propagation to the disturbance, a linear platoon model is established by considering an individual vehicle as a lumped-mass point. Then, the transfer function matrix from disturbance to spacing error is derived for sensitivity analysis. Finally, especially considering the inherent vehicle dynamics, the Burckhardt tire force model is adopted to construct a nonlinear platoon dynamics model for the nonlinear dynamics analysis. The results reveal the characteristics of each platoon configuration, as well as the design of control gains in terms of the anti-disturbing performance.

Abstract Different platoon controls of connected automated vehicles have been studied to improve the entire fleet’s overall energy efficiency and driving safety. The platoons can be used during highway cruising to reduce unnecessary braking, shorten required headway, and thus improve traffic capacity and fuel economy. They can also be used in urban driving to improve traffic efficiency at intersections. However, there remain two problems that prevent the technology from achieving maximum benefit. First, the presence of human-driven vehicles will change the behavior of the fleet and platoon control of connected mixed traffic. Second, the communication uncertainties impose negative impacts on the dynamics of the platoon. A high-performance state predictor for surrounding vehicles can reduce the human-driven vehicle’s influence and help handle communication uncertainties better.

Abstract During the entry and exit of attraction viewing, the rapid generation of travel demand and converging traffic flows in a short period can easily pose safety hazards to people due to its complex terrain. This study aims to propose a path planning method that integrates a dynamic traffic model with the A* algorithm for the planning of scenic routes. The study first combines the cellular transport model (CTM) model with the Greenshield model as its dynamic traffic model and then improves the A* algorithm with the Morphin search tree algorithm (Morphin) as its scenic route planning. The results of the study show that the improved A* algorithm reaches the expected error of 10−4 after 21 ms using Matlab tests, and simulation tests are conducted in regular and complex sections of the scenic area.

Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects.

Abstract Part I introduced the aerodynamic equation of state. This Part II introduces the aerodynamic equation of state for lift and induced drag of flapping wings and applies it to a hovering and forward-flying bumblebee and a mosquito. Two- and three-dimensional graphical representations of the state space are introduced and explored for engineered subsonic flyers, biological fliers, and sports balls.

Abstract The aerodynamic equation of state is introduced in Part I and applies to selected aerospace systems. Part II applies it to the flapping of hovering and forward-flying biological fliers. This last Part III expands the aerodynamic equation of state by adding the potential energy term, assumed up to this point to be zero as the system and its trajectory is placed coplanar with an arbitrary reference potential plane. Part III applies the expanded equation of state to familiar and well-trodden fluid-static and fluid-dynamic cases selected from fluid mechanic textbooks.

Abstract Homogenous lean combustion in a direct-injection spark-ignition (DISI) engine is a promising pathway to achieve significantly improved fuel economy, making already competitive petrol engines even more attractive as a future powertrain option. This study aims to enhance the fundamental understanding of flame growth occurring in a DISI engine with varied charge equivalence ratios of 1.0 to 0.6 while keeping a low compression ratio of 10.5, a typical side-mounted injector, and early injected homogenous charge conditions. A new flame front vector analysis is performed using the flame image velocimetry (FIV) method applied to 100 cycles of high-speed flame movies with trackable contrast variations and pattern changes in the flame boundary. A spatial filtering method is used to decompose the bulk flow component and high-frequency flow component with the latter being interpreted as turbulence.

Abstract TOC

Abstract This study consists of a novel approach based on Classical Mechanics to explain the aerodynamic forces on a body in motion relating to a fluid. This new approach does not require the presence of viscosity to generate the forces and is compatible with the Kutta condition. The physical reasoning of the approach is outlined with the introduction of the aerodynamic suction effect of the body. Next, the mathematical expressions and a code that models the physical phenomena are developed. These are applied for the case of a sphere immersed in a moving fluid and then an airfoil. An initial validation of this new approach is performed by a comparison of the theoretical results and the available results of the National Advisory Committee for Aeronautics (NACA) airfoils. This new mathematical approach is especially valid for high Reynolds numbers where viscosity can be neglected.

Abstract This article aims to analyze the effect of vortex generators (VGs) placed on symmetrical and cambered aerofoil. Simulation and experimental works were carried out using NACA 6321 and NACA 0021 aerofoils at different angles of attack (AOA) and aerodynamic performance obtained at a velocity of 15 m/s and 140625 Reynolds number (Re). In this study, aerofoils with the same thickness and a novel design of minute VGs were introduced and placed at a location of 0.5C (50% of chord). The VGs improved the stall AOA by 4° and 2° in simulation and experimental methods, respectively, with no drag increment compared to the baseline aerofoil. These VGs controlled the boundary layer over an aerofoil with enhancement in aerodynamic efficiency of subsonic aircrafts.

Abstract Black spot distribution is a major indicator of urban traffic safety. Identifying the spatial distribution of black spots at urban centers is fundamental to understanding the causes, types, and severity of accidents. Many studies have investigated the spatial distribution of black spots worldwide. However, few studies have investigated the causes, types, and severity of accidents associated with population size, land use patterns, and prevailing traffic conditions in black spots. This study attempts to explore these associations in the black spots in the Dammam Metropolitan Area (DMA). The data was collected between 2015 and 2019 from the Traffic Police Department and the Department of Transportation of the Saudi American Oil Company. The data was analyzed using several spatial analytical techniques, including statistical and GIS-based techniques.