Aerodynamic Effects of Roof Deflector and Cab Side Extenders for Truck-Trailer Combinations Chalmers Univ. of Technology

Format:

Conference/Event

Author/Creator:

Martini, Martini, author.

Contributor:

Bergqvist, Björn

Hjelm, Linus

Löfdahl, L. (Lennart)

Conference Name:

Commercial Vehicle Engineering Congress (2011-09-13 : Chicago, Illinois, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

Today there are a large variety of drag-reducing devices forheavy trucks that are commonly used, for example, roof deflectors,cab side extenders and chassis fairings. These devices are oftenproven to be efficient, reducing the total aerodynamic resistancefor the vehicle. However, the drag-reducing devices are usuallyidentical for a specific pulling vehicle, independent of the layoutof the vehicle combination.In this study, three vehicle combinations were analyzed. Thetotal length of the vehicles varied between 10.10 m and 25.25 m.The combinations consisted of a rigid truck in combination with oneor two cargo units. The size of the gap between the cargo unitsdiffered between the vehicle combinations. There were also threeconfigurations of each vehicle combination with differentcombinations of roof deflector and cab side extenders, yielding atotal number of nine configurations.The aim of this investigation was to determine the aerodynamiceffects of the roof deflector and cab side extenders as a functionof the type of vehicle combination. Important factors were thetotal length of the vehicle combination and the influence of thedrag reducing devices further downstream. The investigation wasperformed using Computational Fluid Dynamics (CFD).The results from the investigation showed that the effect of thetwo drag-reducing devices analyzed was different depending on thetype of vehicle combination. It was established that the roofdeflector and cab side extenders were always efficient in reducingdrag both in 0° yaw and 5° yaw but the magnitudes differed betweenthe configurations. The largest effects of the drag-reducingdevices were seen for the truck including the 1st cargo unit; theinfluence of the drag-reducing devices on the 2nd cargo unit wassmaller. The aerodynamic reductions were diminishing downstream,why it was concluded that it is of great importance to improve theaerodynamic design of the rest of the vehicle to maintain thepositive effects of the drag reducing devices

Notes:

Vendor supplied data

Publisher Number:

2011-01-2284

Access Restriction:

Restricted for use by site license