Comparative computational analysis of drag-reducing devices for tractor-trailers

Constant rise in fuel price in recent times has caused manufacturers of heavy commercial vehicles (HCV) to turn to efficient aerodynamic design of trucks, wagons, tractors as well as trailers.

The comparative analysis in this study compares the coefficient of drag of the following four aerodynamic configurations of a tractor-trailer combination:

1. Semi-trailer with no devices.

2. Semi-trailer with cab roof fairing.

3. Semi-trailer with the proposed rolling pin device.

4. Semi-trailer with the proposed rolling pin device and the cab roof fairing.

The overall coefficient of drag for the tractor-trailer combination for the above four configurations is computed and compared along with that of individual critical surfaces to analyse the effect of two major drag-reducing devices, the cab roof fairing and the momentum injection rolling pin. The pressure distribution in the flow field around the vehicle is studied to understand the flow mechanisms involved in the reduction in overall drag.