The influence of warning lights on the truck cabins on aerodynamic performance

Abstract In recent development of goods transportation by road, there has been a growing interest in truck aerodynamics as a consequence of increased desire to reduce fuel consumption and emissions. Commercial vehicles have undergone continuous modifications in terms of body design (cabin) and trailers or semi-trailers. There have been and still are areas that disrupt air flow and can be optimized for an improved aerodynamic performance. As part of this areas, the paper will study the influence of beacon lights and light ramps positioned on cabin roof for European type trucks (tractor units). These warning equipment’s are imposed by transportation laws, reason for which eliminating them for achieving described purpose is not an option. In this context, the reduction of aerodynamic coefficient (Cd) can be pursued by analysing and optimizing the dimensions, shape and position for warning lights, in order to reduce the magnitude level of swirling effect. Different configurations of these elements will be tested and their impact in terms of air flow on the truck body will be analysed, with focus on roof area. The study will be done by simulating the interaction between airflow and truck in a virtual aerodynamic wind tunnel. The results will be analysed with the help of parameters like velocities, streamlines and pressures from a theoretical and experimental point of view to find the most viable option for each of the presented elements. The CFD (computational fluid dynamics) numerical simulations for chosen tests will be performed at a speed of 110 km/h considering that it is an often-encountered speed for trucks and also that aerodynamic phenomenology can be BETTER observed. By analysing the results obtained from the performed CFD simulations, the best positions and shapes for the beacon and ramp lights are desired to be identified. The paper conclusions will contain best configurations of warning lights and emissions improvement.