Analysis of the airflow around pick-ups: an experimental description with quantitative and qualitative methods

Abstract

Perhaps the major concern of the transport industry is the product’s performance. It is the factor that makes the product attractive to the consumer. At automobiles, the efforts that go against the engine thrust are the drag and the frictional force between the wheel’s tire and the ground. Thus, this work’s goal is the aerodynamics characterization of the airflow between a very specific class of vehicles: the pickups. Due to the cargo capacity allowed by the bed, this category became representative on the automobile world’s fleet. And so, the bed is one the spotlights when talking about aerodynamics. Because it is an open cavity, the area is prone to the appearance of vortices. Also, the brute difference between the hood and the tail geometry makes the drag to increase. Thereby, this work is the continuation of a major project in development by the Experimental Aerodynamics Research Center of the Federal University of Uberlândia and has as objective the experimental study of this phenomenon by quantitative and qualitative approaches. Thus, two generic pickup models scaled in 1:10 were developed and tested in a wind tunnel at a Reynolds number close to 5x105. The models are simplified from an actual pickup and are equals, except one has live edges and the other rounded edges. In order to fully characterize the airflow between the models, flow visualization technics, the determination of pressure and velocity fields and drag were applied trough the utilization of tufts, smoke, hot-wire anemometry, pressure transducers and an aerodynamics balance. The results to the rounded corners have shown a reduction of approximately 30% on the drag coefficient and a velocity profile with less intense variations. In matters of the visualization, the rounded corner model has presented an airflow smoother in the transition between surfaces and more soft recirculation zones and boundary lawyer detachment.