Impact of the form of a trailer on its aerodynamic performance

Abstract

Today, energy efficiency is a topic of great importance not only due to limited energy resources, but also their impact on environment. In the case of vehicles, great effort is being spent on reducing weight and making the form more and more aerodynamic to reduce fuel consumption and increase energy efficiency. However, there is a limit to this form because a vehicle should never lose traction. A highly aerodynamic form reduces the downward force which provides the vehicle its traction. A trailer with a highly aerodynamic form was investigated to determine if it would lose traction at different speeds and under different wind conditions. Simulations were carried out using the CFD commercial code ANSYS CFX to determine the flow field and the forces (lift, drag, downward force, etc.) around the trailer. The calculation domain was taken large enough not to affect the flow field. The partial differential turbulent flow equations (continuity, momentum, and turbulence equations) were solved in three dimensions to find the velocity and pressure distributions. Different trailer forms were also investigated. The type of vehicle towing the trailer also has an impact on the flow field around it. Thus, different types of vehicles were considered in the simulations. The results demonstrated that certain forms could cause the loss of traction at high enough speeds. In this article, the model is explained, and the results of a number of cases are presented and discussed.