Renewable Energy from Induced Airflow Generated by Cruising Ground Vehicles in Tandem using RANS

Abstract

Wind is one renewable energy source which can exist naturally when there are changes in the atmospheric weather conditions. One other source of wind energy is generated by passing vehicles cruising along roads, streets or highways. If this energy from the induced airflow is harnessed it can be used for highway lighting as well as for emergency signage (LED) respectively for breakdown vehicles, narrow bridges, low overhead bridges, highway under repairs, etc. To understand the characteristics of this induced airflow on how the energy is distributed, a threedimensional airflow structure of simplified passenger cars of Ahmed model in tandem, of two or more, was investigated comprehensively. This study was conducted using a numerical analysis by adopting a well-known equation of Reynolds Averaged Navier Stoke (RANS) which, as reported by previous researchers, offers a good compromise between accuracy of the result and the computational cost. The result shows that the turbulence kinetic energy generated by the car during cruising is of a fairly high magnitude and getting higher at higher speeds of car travel. The effects of vehicles travelling in a queue are demonstrated to give a clear result of high turbulence kinetic energy which occurs at its two sides of downstream region while the maximum kinetic energy is developed in the wake region behind the trailing car. For the purpose of energy recovery, these simulated flow patterns are useful in determining, for example, a right location to install a small wind turbine which can be used to convert the waste kinetic energy into useful electrical energy.