Transient Wind Shear and Tail-Pipe Emissions from Passing Vehicles under a Freeway Overpass with and without Crosswind

Among elements of an intelligent transportation system for autonomous vehicles are embedded sensors for vehicle-to-structure and vehicle-to-road communications. Continuous operation of these sensors requires a local electric power supply, especially in remote areas. Electric power sources are also needed for the structural health monitoring system, that is, for detecting any structural damage, whether natural (i.e. earthquake) or manmade (i.e. accident). Recently we have completed part I of our unsteady numerical investigations for a generic vehicle (Ahmed body) passing under a freeway overpass at different distances from the side bridge columns.

Principal Investigator: 

Hamid Rahai

PI Contact Information: 

hamid.rahai@csulb.edu

California State University, Long Beach

Dates: 

January 2021 to December 2021

Impacts/Benefits of Implementation: 

The study aimed at understanding the wind load on the bridge columns and wind energy potential generated from the passing vehicles at different distances from these columns under a typical freeway overpass that could be used for generating electric power. Results have shown that when the vehicle is at 0.75W distance from the bridge columns, an unsteady wind speed of up to 24 m/s is generated at the columns with a pressure coefficient of 0.9. Here W is the width of the vehicle. These results indicate with an appropriate system for harnessing these wind energy potentials, significant renewable electric power could be generated with zero carbon footprint.

In parts II & III of the project during years 3 &4, the investigations are focused on the detailed physical understanding of the interaction of wind shear from passing multiple vehicles with the bridge columns with and without crosswinds. The study will also investigate the dispersion and diffusion of tailpipe emissions and whether there is a benefit of having a carbon-capturing system under the freeway overpass to reduce local air pollution concentration.

Project Number: 

2145