AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Comparing Different VIT Formulations on Near-Road Dispersion of Particulate and Gaseous Pollutants
KHALED HASHAD, Bo Yang, Vlad Isakov, K. Max Zhang, Cornell University
Abstract Number: 607 Working Group: Passive Mitigation Strategies to Reduce Exposure to Near-Road Air Pollution
Abstract Traffic-related air pollution is associated with a range of health issues including respiratory and cardiovascular problems, birth defects, and cancer. Recent studies suggest that the presence of roadside barriers can potentially mitigate exposure to air pollution for those living and working close to major roads. As vehicle-induced turbulence (VIT) has a strong effect on the initial dispersion of pollutants, it would be challenging to explore the impact of roadside barriers without a proper understanding of VIT. Our study compares three different techniques to model VIT. The first method models VIT as a fixed volume source where turbulence is uniformly produced in the highway computational domain. The second method treats each highway lane as a forcing zone where an estimate for the drag force produced by vehicles in that lane would be imposed into the domain. The third method distributes the drag force of each vehicle into the domain using a Gaussian function such that computational grid points close to vehicles would experience a strong forcing as opposed to grid point further away. To evaluate the accuracy of each method, the simulation results are compared to experimental data obtained in an USEPA field study on a major highway in Las Vegas. The experimental data include extensive, collocated measurements of traffic, turbulence and air pollutant concentrations. The turbulent kinetic energy and pollutant concentration obtained from the simulations are compared with those of the field study. The impact of VIT on pollutant dispersion will also be explored for the different techniques.