Velocity Conditions Research Articles

Multi-scale non-uniform hierarchical filtering model based on fractal theory.

Gasoline particulate filters (GPF) are widely used due to their superior environmental benefits, but its trapping efficiency is affected by many factors. We established a multi-scale non-uniform hierarchical filtering model (MNHF) based on the fractal theory to accurately analyze the dynamic changes of trapping efficiency during GPF operation. The multi-scale characteristics of the filter wall about trap diameter and pore size are presented. Additionally, filter theory and Brownian kinematics are used to precisely predict particle motion. The study focuses on the dynamic change of trapping efficiency of MNHF in different particle size ranges. The results indicate the following: By comparing the numerical simulation results of the model with experimental data, the maximum relative error range is found to be within 0.7%. The MNHF model accurately predicts the change in trapping performance at different times when particles move in the trap. The trapping efficiency of the upper layer of the single-layer trap is higher than that of the lower layer based on the particles' moving distance in unit time, and the trapping efficiency of the next layer is reduced by up to 29.34% compared to that of the upper layer. Additionally, it provides a more accurate simulation of the trapping efficiency for particles with sizes ranging from 0.01 μm to 0.5 μm under conditions of low wall flow velocity.

Experimental study on the flow field inside soap bubble at different incident velocities

Bubbles are widely present in nature. However, previous scientific studies have primarily focused on the development of the outer contour of the bubble while neglecting the changing behavior of the internal flow field due to the difficulty in implementing experiments. This study designs a simple experimental device that can conveniently observe changes in the flow field inside the bubble while avoiding the tedious operation and high costs associated with the particle image velocimetry (PIV) system. Accordingly, this experiment investigates the development process of the flow field inside the bubble and the velocity conditions required for bubble formation for different incident velocities and Reynolds numbers. The study first examines the minimum flow velocity necessary for bubble formation. Then, under low-speed conditions, the flow inside the straw is laminar, and the flow field inside the bubble exhibits a single vortex structure. Under high-speed conditions, the flow inside the straw transitions to turbulent flow, and the flow field inside the bubble exhibits a four-vortex structure. The formation process of this four-vortex structure shows variations as the flow velocity increases. In addition, this study proposes corresponding physical models for bubble formation under low and high flow velocities and verifies the models.

Rigid body in compressible flow with general inflow–outflow boundary data

The paper deals with the problem of the motion of a rigid body in a domain filled by the compressible fluid. We consider the nonhomogeneous boundary condition of the velocity and inflow boundary condition for the density. The existence of the weak solutions is shown. The novelty lies in the fact we are considering the general inflow–outflow boundary data, which were not considered before in the context of fluid–structure interaction.

Dependence of Nonlinear Elastic Parameters of Consolidated Granular Media on Temperature in the Ambient Range

Hysteretic nonlinear elasticity is often observed in consolidated granular media, including concrete, mortar, sandstones, or rocks. Nonlinearity is frequently quantified using Nonlinear Resonant Ultrasonic Spectroscopy (NRUS), which provides tools to define nonlinear parameters for both fast and slow dynamic effects, often observed when analyzing the propagation velocity dependence on strain in such materials. The dependence of these parameters on temperature was studied with the aim of using NRUS to quantify the induced thermal damage; thus, experiments were performed spanning a wide temperature range. However, since most of these materials are used in construction (concrete and sandstone, mostly), it is of interest to understand how sensitive the measured nonlinear parameters are to small environmental temperature fluctuations. In this paper, the dependence on temperature of elastic parameters is investigated, both linear (wave velocity and damping) and nonlinear (the slope and hysteresis of the curves describing the strain dependence of wave velocity and residual conditioning effect on wave velocity), separating the slow from the fast dynamic properties of nonlinearity. The observations reported here denote a different behavior for concrete and Berea sandstone.

Enhanced Tribological Performance of Laser-Textured TiN-Coated Ti6Al4V Alloy Surfaces: A Comparative Study with Untextured Surfaces

Titanium alloy is widely used as a biomaterial due to its strength, lightweight nature, and corrosion resistance. Despite its strength and lightweight nature, its low wear resistance limits its uses in prosthetic components. Laser surface texturing (LST) was used to improve the wear resistance of titanium alloys by creating textured surfaces before applying protective coatings. A biocompatible TiN composite protective coating was applied using physical vapour deposition (PVD) with a thickness of 4 µm. Response surface methodology (RSM) was used to predict the tribological properties by varying input parameters such as material type (TI, T2, T3, and T4), load in N, and sliding velocity in m/s. A pin-on-disc tribometer was used to conduct a unidirectional sliding wear test based on the RSM design. Tribological properties were studied to determine the impact of laser texturing on the bonding strength of the coating. As a result, material type T4 exhibits an improved coefficient of friction and specific wear resistance under varying sliding velocity and load conditions compared to other material types. The study was further supported by an ANSYS simulation, which revealed stress reduction affecting the coefficient of friction and, consequently, wear. The textured surface topography, wear mechanisms, and coating compositions were examined using scanning electron microscopy.

Effect of water mist system settings on fire and upstream smoke control in a longitudinally ventilated tunnel

The effect of Water Mist System (WMS) settings on fire Heat Release Rate (HRR), smoke gas temperature, smoke blocking effectiveness and required critical velocity were investigated in a 3 m (width)× 2.2 m(height)× 30 m (length) tunnel model equipped with longitudinal ventilation (LV). A total of 60 tests were conducted in 12 configurations, varying the nozzles position, nozzle row number and nozzles pressure. Additionally, 5 bucket tests were also carried out to assess the influence of LV on water mist trajectories. The bucket test results revealed a strong correlation between fire HRRs and the “local” water quantity on the ground near the fire source, particularly for smaller fires. The WMS’s effectiveness in reducing the maximum smoke gas temperature rise and critical velocity largely depends on the nozzles which are placed closest to the fire source to a great extent. Reducing the distance to the fire source or increasing water flow rates could both enhance the reduction effect. However, activating additional upstream nozzle rows provides minimal benefit, as the interaction between adjacent rows becomes negligible at higher LV velocities. In contrast, increasing the number of nozzle rows can enhance smoke blocking effectiveness, as measured by the confinement velocity reduction rate. The findings demonstrate that the entrainment and blockage effect of WMS are the primary determinants of the smoke back-layering (BL) degree under the confinement velocity conditions, rather than the smoke cooling effect. Furthermore, positioning the WMS upstream of the fire source and maintaining a certain distance can optimize the combined effects of WMS and LV on fire HRR and smoke back-layering control, which is partly due to the water mist deflection under ventilation flow. This preliminary study provides foundational data on fire and smoke control using water mist in longitudinally ventilated tunnels and offers insights for the optimal design of WMSs.

Investigation of drafting-kissing-tumbling movement of two particles with conjugate heat transfer

The conjugate heat transfer at the particle-fluid interface and the collision between particles play a crucial role in the sedimentation process of particles. In this work, the recent volumetric lattice Boltzmann method for thermal particulate flows with conjugate heat transfer is adopted to investigate the drafting-kissing-tumbling movement in the sedimentation process of two particles in a closed channel. This volumetric lattice Boltzmann method is based on double distribution functions, with the density distribution function used for the velocity field and the internal energy distribution function used for the temperature field. It is a single-domain approach, and the nonslip velocity condition within the solid domain can be strictly ensured. The difference in thermophysical properties between the solid and fluid can be correctly handled, and the conjugate heat transfer condition can be automatically achieved without any additional treatments. Based on this particle-resolved simulation, the influences of the solid-to-fluid specific heat ratio, the Grashof number, and the particle’s initial temperature on the drafting-kissing-tumbling movement are discussed in detail. It is found that the fluid cooled by the particle and thus subjected to the downward buoyancy force can promote particle sedimentation. As the specific heat ratio increases, the particle’s temperature rises relatively slowly. In the sedimentation of two cold particles, the drafting duration and tumbling duration of the drafting-kissing-tumbling movement decrease when the heat capacity ratio increases. In contrast, the kissing duration increases as the heat capacity ratio increases. When the Grashof number increases, the heat transfer between the particle and fluid is enhanced, and the drafting duration significantly decreases while the kissing duration and tumbling duration remain almost unchanged in the sedimentation of two cold particles. The particle’s initial temperature greatly affects the occurrence moment of the drafting-kissing-tumbling movement. To be specific, the drafting-kissing-tumbling movement occurs at the earliest moment for the sedimentation of two cold particles, followed by the sedimentation of one cold and one hot particle, and the latest for the sedimentation of two hot particles. The promoting effect of the low particle’s initial temperature on the drafting-kissing-tumbling movement mainly takes place in the dragging stage and kissing stage. The particle’s initial temperature has almost no influence on the tumbling duration.

Constraint-oriented formation control of multi-robot system in leaderless consensus under confined conditions

In this paper, constraint-oriented coordination control of a first-order multi-robot system has been considered in a leaderless consensus where rectangular velocity components of participating robots are subject to constraints while also avoiding inter-robots collisions. The desired formation control of different robots and their inter-robots collision avoidance in a team of robots are achieved by solving an optimization problem based on control barrier functions whereas graph theory concepts are used to represent the interaction relations among robots. A devised quadratic programme subject to the velocity and safety conditions, minimizes the desired cost function encoded in the control barrier function and generates separate control inputs for each robot. The rectangular components of the velocity against each robot are kept constrained during the entire operation of the formation control. The optimization-technique-based decentralized controllers were simulated in MATLAB and the corresponding results were recorded. The robots in the team successfully attained the desired formation in a leaderless consensus, deploying themselves in a plane under constrained rectangular velocities without colliding with each other. Several simulation examples with different values of velocity constraints have been shown to illustrate the operation of constrained controllers while ensuring that the desired leaderless-consensus-based formation remains attainable in a safe manner.

Phobia situations increase body sway in young adults

BACKGROUND: Recent studies have analyzed the influence of emotional state. However, most of these studies employed questionnaires exclusively and were conducted outside the context of the phobic episode. AIM: The study aimed to investigate how phobia interferes with body sway in younger adults. METHOD: Thirty-seven adults participated in the study and underwent a postural control assessment in which participants should maintain an upright static position while watching a video. They performed three conditions: pre-phobia, which involved viewing neutral images; phobia phase, which involved viewing images based on the previous phobia and fear questionnaire; and post-phobia phase, which involved viewing neutral images. Body sway was measured using a Vicon Motion System® - 200 Hz. Three passive markers were positioned on pre-determined anatomical landmarks of the body. The following parameters were analyzed: anterior-posterior and medial-lateral amplitude, mean velocity and displacement, and the entire oscillation trajectory. RESULTS: The ANOVA indicated the effect of phobia by analyzing the conditions of anterior-posterior displacement (F2,22 = 10.067, p <0.001) and mean velocity (F2,22 = 11.142, p <0.001). The phobia condition showed higher anterior-posterior displacement and mean velocity values than the pre- and post-phobia conditions (p <0.001). CONCLUSION: The findings indicated an increase in body sway in phobia situations, suggesting that individuals should avoid situations requiring balance when exposed to phobic stimuli.

The Measurement of Spatiotemporal Parameters in Running at Different Velocities: A Comparison Between a GPS Unit and an Infrared Mat.

The accurate measurement of spatiotemporal parameters, such as step length and step frequency, is crucial for analyzing running and sprinting performance. Traditional methods like video analysis and force platforms are either time consuming or limited in scope, prompting the need for more efficient technologies. This study evaluates the effectiveness of a commercial Global Positioning System (GPS) unit integrated with an Inertial Measurement Unit (IMU) in capturing these parameters during sprints at varying velocities. Five experienced male runners performed six 40 m sprints at three velocity conditions (S: Slow, M: Medium, F: Fast) while equipped with a GPS-IMU system and an optical system as the gold standard reference. A total of 398 steps were analyzed for this study. Step frequency, step length and step velocity were extracted and compared using statistical methods, including the coefficient of determination (r2) and root mean square error (RMSE). Results indicated a very large agreement between the embedded system and the reference system, for the step frequency (r2 = 0.92, RMSE = 0.14 Hz), for the step length (r2 = 0.91, RMSE = 0.07 m) and the step velocity (r2 = 0.99, RMSE = 0.17 m/s). The GPS-IMU system accurately measured spatiotemporal parameters across different running velocities, demonstrating low relative errors and high precision. This study demonstrates that GPS-IMU systems can provide comprehensive spatiotemporal data, making them valuable for both training and competition. The integration of these technologies offers practical benefits, helping coaches better understand and enhance running performance. Future improvements in sample rate acquisition GPS-IMU technology could further increase measurement accuracy and expand its application in elite sports.

SURFACE INVESTIGATION OF HIGH TEMPERATURE WEAR BEHAVIOR OF SS316L ALLOY PRODUCED BY LASER POWDER BED FUSION

This research investigates the tribological characteristics of SS316L produced through Laser Powder Bed Fusion (LPBF), emphasizing the influence of testing temperature, sliding velocity, and loading conditions. The findings demonstrate that the friction coefficient escalates with increased temperatures (150°C and 250°C), whereas the wear rate remains invariant, presumably attributable to the establishment of a lubricating surface layer. The rotational velocity of 300 revolutions per minute the Coefficient of Friction (COF) shown an upward movement although the wear rate remains constant. The findings underscore the importance of analyzing different parameters to understand the friction and wear properties of additively manufactured SS316L.

Thermal Performance of Nanofluid Flow Along an Isothermal Vertical Plate with Velocity, Thermal, and Concentration Slip Boundary Conditions Employing Buongiorno’s Revised Non-Homogeneous Model

This study examines the natural convection of a steady laminar nanofluid flow past an isothermal vertical plate with slip boundary conditions. A review of existing literature reveals no prior research that has explored the combined effects of thermophoresis, Brownian diffusion, and particle electrification while considering slip boundary conditions in nanofluid flow. Buongiorno’s revised four-equation non-homogeneous model, incorporating mechanisms for thermophoresis, Brownian diffusion and particle electrification, is utilized to address this gap. The model employs velocity, thermal, and concentration slip boundary conditions to investigate enhancing the nanofluid's thermal conductivity. The resulting local similar equations are tackled using MATLAB's bvp4c package. The study discusses the influence of key parameters, such as thermophoresis, Brownian motion, and electrification, on temperature, velocity, and concentration distributions, as well as on heat, mass transfer and skin friction coefficients. The findings of the simulation are consistent with previous studies, showing that an improvement in the electrification parameter rises the heat transfer coefficient, while thermophoresis and Brownian motion parameters have the opposite effect. Additionally, mass transfer coefficient values increase with higher Brownian motion and electrification parameters while reducing with the thermophoresis parameter. This physical model has potential applications in heat exchangers using nanofluids and in cooling plate-shaped products during manufacturing processes. The novelty of this study lies in the analysis of Brownian diffusion, thermophoresis, and particle electrification mechanisms in nanofluid flow under slip boundary conditions.

Interpretable machine learning modeling of temperature rise in a medium voltage switchgear using multiphysics CFD analysis

In recent decades, leading companies and research groups have extensively conducted Multiphysics computational fluid dynamics (CFD) analyses to evaluate temperature rise in switchgear systems, aiming to meet type-testing requirements specified in IEC standards. However, the complex interaction of geometrical and operational parameters presents significant challenges in interpreting these methods. Artificial intelligence (AI) algorithms have gained attention in various engineering fields to address similar issues. This paper investigates the influence of four key manufacturing and operational parameters, both categorical and continuous, on temperature rise in a medium voltage (MV) switchgear case study. A CFD-based dataset was created from these parameters to target maximum temperature, facilitating the study's objective. Several models for temperature rise estimation, including extreme gradient boosting (XGBoost), support vector regression, decision tree, and random forest, were compared. An explainable artificial intelligence (XAI) technique, Shapley Additive Explanations (SHAP), was applied to the best-performing model to evaluate the importance of each feature in predicting maximum temperature. The results revealed that XGBoost provided the most accurate predictions, with a scatter band (SB) of ±1.01 and average R2 values of 99.98 % and 96.59 % for the training and testing sets, respectively. SHAP analysis identified the most significant variables affecting temperature prediction as current, air velocity, duct area, and switchgear conditions, in that order.

Study of Sand Transport in a Horizontal Pipeline Using Validated Computational Fluid Dynamics Simulations with Experimental Fiber-Optic Distributed Acoustic Sensing Data

Summary Sand management in wellbores is a significant challenge in the industry, notably impacting equipment integrity and operational safety—particularly in offshore oil and gas operations affected by the onset of sand production along with hydrocarbons. Recent advancements in fiber-optic sensing, especially through distributed acoustic sensing (DAS) experimental data, have enabled the continuous monitoring of sand ingress and migration. In this study, we use computational fluid dynamics (CFD) to accurately model sand transport by validating the simulations against the DAS data in a 40-ft-long, 2-in.-diameter experimental flow loop. The validation and verification (V&V) process demonstrates the CFD model’s accuracy in both steady-state and transient conditions, through predictions of key flow parameters such as sand slip velocity, sand concentration profiles, and sand arrival times against published experimental data, as well as verification of CFD methodology against similar simulation studies. Next, we used the CFD model to simulate the fiber-optic experimental DAS data for sand slurry transport in a pipe through an injection port with conditions of carrier fluid velocity = 0.93 m/s and dispersed phase (sand) particle diameter of 300 µm at a concentration of 0.001 v/v. To address uncertainties during sand production, a parametric study under transient conditions was conducted with varying boundary conditions in the CFD model. It examined fluid flow velocities at both 0.53 m/s and 0.93 m/s, below and above the critical settling velocity of the sand respectively, and the effects of varying sand particle diameters (125 µm and 600 µm). Our research represents a significant advancement in sand management strategies, offering a robust and cost-effective tool for simulating real-world scenarios to improve operational efficiency. By providing detailed insights into flow dynamics and enabling robust predictions across various conditions, this study contributes substantially to advancing sand management strategies that could effectively mitigate operational risks and optimize sand transport in real time.

Comparação de métodos para determinação do fator solar de vidros

Abstract Solar Heat Gain Coefficient (SHGC) is a thermal property of glass and transparent elements, defined as the ratio between the amount of solar energy that passes through the glass and the amount of solar energy that reaches it. SHGC can be determined using mathematical models, computer simulations, or field and laboratory measurements. This paper compares the methods for obtaining the SHGC, which include laboratory measurements using a portable calorimeter, computer simulation using the WINDOW software and calculated according to ISO 9050 standard. Two solar control glasses and one clear glass, used as a reference, were selected. The SHGCs obtained using laboratory measurements were lower than those obtained using the other methods due to the solar simulator and equipment limitations. Despite this, there was a good approximation of the behaviour of the glasses regarding the increase in air velocity. The heat transfer coefficient on the exterior surface was fixed, so the SHGC obtained for each glass based on ISO 9050 remains the same, regardless of the air velocity. The SHGC results based on ISO 9050 were similar to those measured by means of a portable calorimeter under conditions of higher air velocities.

Modeling and verification of an improved contact force in multibody systems

In many engineering applications, contact and collision phenomena are commonly observed in multibody systems, which can lead to issues such as dynamic output oscillations, reduced motion accuracy, decreased reliability and lifespan, and even functional failures in mechanical systems. To more accurately describe common collision phenomena and their impact on the dynamic characteristics of multibody systems, this paper introduces a contact force model with improved nonlinear stiffness and damping coefficients. This model is based on Hertz theory and considering the relationship between indentation and velocity during the collision process by incorporating a nonlinear index factor, m. Additionally, the Newton restitution coefficient is used as an evaluation criterion to verify the effectiveness of the improved model. Numerical analyses were conducted on single collisions between joints at different initial collision velocities and restitution coefficients, using both the proposed improved contact force model and existing classical models. Further numerical simulations of steel ball collisions were performed using the improved model, and the results were compared with experimental test data. Ultimately, the study results demonstrate that the improved contact force model is more accurate and effective than existing classical models under various restitution coefficients and collision velocity conditions, and has a wider range of applicability.

Research on aerodynamic and ballistic characteristics of rotary wing type aerodynamic layout rocket

Abstract Rockets with a rotating wing type pneumatic layout as the research object, using the method of numerical simulation of subsonic stage of the rocket was studied at different attack angles, Mach Numbers and aerodynamic characteristics under different conditions of rudder Angle, and obtained the corresponding pneumatic parameters, and the influence of the relationship between the aerodynamic parameters. The motion equations of rocket are established, the force and moment of rocket during flight are analyzed, and the ballistic characteristics under different muzzle velocity and different launch elevation are simulated and analyzed, and the ballistic effects of different muzzle velocity conditions are obtained.

Dynamics of localized waves and interactions in a [formula omitted]-dimensional equation from combined bilinear forms of Kadomtsev–Petviashvili and extended shallow water wave equations

This work investigates new exact solutions within a unique (2+1)-dimensional problem by combining the Hirota bilinear forms of the Kadomtsev–Petviashvili and the Shallow Water Wave equations. We obtain resonant Y-type and X-type soliton, breather, and lump waves by introducing novel limitations on the N-soliton. Additionally, it generates various types of solutions (bulk-soliton, fissionable soliton-lump, breather-lump, and soliton-breather-lump) based on velocity and module resonance conditions. Furthermore, we investigate the lump wave’s paths interacting with the waves prior to and following collision using the long-wave limit approach. We show that the lump wave either avoids collision with other waves or maintains a persistent state of collision with them by applying additional limitations. Specifically, we provide a series of figures depicting all solutions, comprehensively capturing their dynamical behavior and interactions.

Flame emission spectroscopy measurement and comprehensive characterization of various spray flames in a turbulent swirl burner

In this study, a spray swirling combustion system focusing on five liquid fuels: methanol, ethanol, heptane, aviation kerosene, and sustainable aviation kerosene is built, and the combustion characteristics of spray swirling flames based on OH*, CH*, and C2* chemiluminescence characterization are further investigated. Subsequently, a quantitative model relating the chemiluminescence intensities of OH*, CH*, and C2* to the flame parameters is established, providing essential data for studying spray swirling flames. Results showed that the combustion efficiencies of the spray swirling flame for five liquid fuels positively correlate with the equivalence ratio and the airflow exit velocity. Yet the linearity between the chemiluminescence intensities of OH*, CH*, and C2* and the equivalence ratio is relatively low, and the efficacy of the intensity ratios OH*/CH*, OH*/C2*, and CH*/C2* in characterizing the equivalence ratio is limited. The correlation coefficients of the quadratic polynomial fitting between the chemiluminescence intensity ratio of OH*·C2*/CH* and the equivalence ratio exceed 0.98 under any airflow exit velocity condition, making it the optimal indicator for characterizing equivalence ratio in spray swirling flames. For the heat release rate, a power-law model based on the chemiluminescence intensity is proposed, demonstrating significantly higher effectiveness compared to the traditional linear models. The three-species power-law model utilizing the OH*, CH*, and C2* chemiluminescence intensities achieves the fitting accuracy exceeding 98% across the five fuels, providing a robust quantitative characterization for heat release rate in spray swirling flames. However, employing the chemiluminescence of single or two of the three radical species to determine heat release rates in liquid fuels lacks universality.

Is driving an electric two-wheeler (E2W) safe? Analysing safety risk factors of E2W considering the quality and reliability criteria

PurposeThe purpose of this research is to identify and analyse the perceived risk factors affecting the safety of electric two-wheeler (E2W) riders in urban areas. Given the exponential growth of the global E2W market and the notable challenges offered by E2W vehicles as compared to electric cars, the study aims to propose a managerial framework, to increase the penetration of E2W in the emerging market, as a reliable, and sustainable mobility alternative.Design/methodology/approachThe perceived risk factors of riding E2Ws are relatively scanty, especially in the context of emerging economies. A mixed-method research design is adopted to achieve the research objectives. Four expert groups are interviewed to identify crucial safety risk E2W factors. The grey-Delphi technique is used to confirm the applicability of the extracted risk factors in the Indian context. Next, the Grey-Decision-Making Trial and Evaluation Laboratory (DEMATEL) technique is employed to reveal the causal-prominence relationship among the perceived risk factors. The dominance and prominence scores are used to perform Cause and Effect analysis and estimate the triggering risk factors.FindingsThe finding of the study suggests that reckless adventurism, adverse road conditions, individual characteristics and distraction caused by using mobile phones, as the topmost triggering risk factors that impact the safety of E2Ws drivers. Similarly, reliability on battery performance low velocity and heavy traffic conditions are found to be some of the critical safety factors.Practical implicationsE2Ws are anticipated to represent the future of sustainable mobility in emerging nations. While they provide convenient and quick transportation for daily urban commutes, certain risk factors are contributing to increased accident rates. This research analyses these risk factors to offer a comprehensive view of driver and rider safety. Unlike conventional measures, it considers subjective quality and reliability parameters, such as battery performance and reckless adventurism. Identifying the most significant causal risk factors helps policymakers focus on the most prominent issues, thereby enhancing the adoption of E2Ws in emerging markets.Originality/valueWe have proposed an integrated framework that uses grey theory with Delphi and DEMATEL to analyse the safety risk factors of driving E2W vehicles considering the uncertainty. In addition, the amalgamation of Delphi and DEMATEL helps not only to identify the pertinent safety risk factors, but also bifurcate them into cause-and-effect groups considering the mutual relationship between them. The framework will enable practitioners and policymakers to design preventive strategies to minimize risk and boost the penetration of E2Ws in an emerging country, like India.