Car and caravan dynamic stability under crosswind

The work of this thesis concerns the behaviour of a car towing a caravan in crosswind condition. This situation is of particular interest because it can lead to dangerous situations. In fact, especially at high speed, it can affect the stability of the system and it can cause crashes. Even if there is not a strong wind and a high speed, this system is more prone to instability than a single car due to the fact that the motion of the trailer affects the behaviour of the car. As a consequence, on the road there are particular restrictions for this type of vehicle like lower speed limit. The aerodynamic of a car towing a caravan has been studied a lot in the past in order to avoid this problem and to find solutions that were able to reduce the drag coefficient and so the fuel consumption. A few studies have been dedicated to the analysis of the effect of crosswind on such systems, however this dangerous situation, that can lead to the instability, is not solved yet. In this thesis the behaviour of a car towing a caravan with different crosswinds and different speeds has been analysed through a mathematical model describing the dynamic of the system. The forces that have been generated by the action of the wind are calculated by CFD computation. Then the aerodynamic models have been validated comparing them with experimental results obtained through wind tunnel tests.

In questo lavoro è stato svolto uno studio sul comportamento di un'auto trainante un caravan in condizioni di vento laterale. Per lo studio aerodinamico sono state svolte delle analisi CFD unite a studi in galleria del vento. Per studiare gli effetti del vento laterale è stato studiato il comportamento dinamico del veicolo tramite un modello matematico a più gradi di libertà.