Modeling Emission Flow Pattern of a Single Cruising Vehicle on Urban Streets with CFD Simulation and Wind Tunnel Validation

Abstract

Transportation has become one of the primary sources of urban atmospheric pollutants and it causes severe diseases among city residents. This study focuses on assessing the pollutant dispersion pattern using computational fluid dynamics (CFD) numerical simulation, with the effect and results validated by the results from wind tunnel experiments. First, the wind tunnel experiment was carefully designed to preliminarily assess the flow pattern of vehicle emissions. Next, the spatiotemporal distribution of pollutant concentrations around the motor vehicle was modeled using a CFD numerical simulation. The pollutant concentration contours indicated that the diffusion process of carbon monoxide mainly occurred in the range of 0−2 m above the ground. Meanwhile, to verify the correctness of the CFD simulation, pressure distributions of seven selected points that were perpendicular along the midline of the vehicle surface were obtained from both the wind tunnel experiment and the CFD numerical simulation. The Pearson correlation coefficient between the numerical simulation and the wind tunnel measurement was 0.98, indicating a strong positive correlation. Therefore, the distribution trend of all pressure coefficients in the numerical simulation was considered to be consistent with those from the measurements. The findings of this study could shed light on the concentration distribution of platoon-based vehicles and the future application of CFD simulations to estimate the concentration of pollutants along urban street canyons.

Research on precise and standardized numerical simulation strategy for vehicle aerodynamics

“…The calculated results are consistent with those of a wind tunnel test. Based on the standard k-ε model, the calculated pressure coefficients are consistent with the experimental results (Shi et al , 2020). Using the renormalization group (RNG) k-ε model and the semi-implicit method for pressure-linked equations-consistent (SIMPLEC) pressure-velocity coupling algorithm, Wang et al (2021) conducted a numerical study on the flow around a vehicle model.…”

An Optimized Artificial Neural Network Model using Genetic Algorithm for Prediction of Traffic Emission Concentrations

“…in China, 85% of emissions were from transport [15], while in the United Kingdom was 92% [16], and 75% in Malaysia [17], but in the United States, automobiles are responsible for emitting 57% of air pollution [7]. Many other studies also show that 92% of CO and 65% of hydrocarbon (HC) pollutants were emitted from the transportation activities in Shanghai [18], and 60% of N O x and P M emissions were from heavy-duty trucks in China [19].…”