Final project of the course

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Numerical and Experimental Analysis of Aerodynamic Tail Devices for Drag Reduction of a Semi-Trailer Final project of the Aerodynamics of Transport Vehicles course Group: F rancesco Lorenzo Alice, 10678140 Alessandro Crotta, 10621786 Matteo Dall’Ora, 10687723 Lecturers: Prof. Luigi Vigevano Prof. Paolo Schito Ing. Francesco Fabio Semeraro 1. Introduction In the last decades, aerodynamic performance and drag reduction have played a central role in the design process of production vehicles, often clashing with overall dimensions and aesthetic goals, as today’s demand of reducing fuel consumption is one of the most challenging issues within the automotive industry. When long-haul commercial vehicles are concerned, the issue acquires an even greater importance as single percentage points of fuel saving can make a significant difference. In most cases, yet, semi-trailers external shape is nowadays still driven by the need of optimizing the internal storage capability while keeping overall dimensions limited in compliance to local regulations, limiting the room of improvement to external add-ons or minor shape changes. Multiple drag reduction devices have already been conceived and tested, showing promising results both in literature studies and practical applications, with some of them being commonly adopted by the latest production vehicles; this category includes roof spoilers and fairings, side skirts and more rounded and well-designed A-pillars and side mirrors. In spite of the effectiveness of these features, none of them directly targets the main source of trucks aerodynamic drag, being the large, low pressure separation bubble present at the back of the trailer. While boat tails and frame extensions do exist and have had a decent amount of research put into their…