Advanced bobsleigh design. Part 2: aerodynamic modifications to a two-man bobsleigh

Abstract

The aim of the present study is to improve the aerodynamic performance of the bobsled as a function of its shape and the relative position of the athletes inside the bobsled. This performance optimization problem is studied by means of wind tunnel testing. The aerodynamic responses of the manned and unmanned bobsleigh are analysed in terms of overall drag force measurements. Experimental results show that the proposed modi cations to the sidewalls and the nose section of the bobsled improve its drag performance. The relative position of the driver and the brakeman has a great in uence on the drag of the bobsled.

Aerodynamic drag reduction in winter sports: The quest for “free speed”

“…Practical solutions to increase pressure inside the cavity, such as sidewall flaring or extending the arms of the brake person along the top of the cavity, have not proven to be effective. 50,64 The results of other studies have suggested that streamlining the bumpers or altering the front of the cowling by the addition of two rounded humps do not consistently reduce drag at race velocities. 62,64,66 Full-scale wind tunnel test results.…”

“…50,64 The results of other studies have suggested that streamlining the bumpers or altering the front of the cowling by the addition of two rounded humps do not consistently reduce drag at race velocities. 62,64,66 Full-scale wind tunnel test results. As fractional scale model tests may omit construction details or provide only rough approximations of the bobsleigh or crew, the current research measured the aerodynamic drag of full-scale 2-and 4-person bobsleighs, with and without their crews, in a wind tunnel with simulated track walls positioned alongside the bobsleigh.…”

“…1. changing the position of the pushers behind the pilot and streamlining the driver's helmet as the rules of the International Bobsleigh and Skeleton Federation (''IBSF'') require a convex cowling and extensive design controls that limit the potential for reduction of the bobsleigh's frontal area 51,64 ; and 2. methods to reduce the formation of a low-pressure area inside the cowling as flow visualization and PIV studies have identified that two counterrotating vortices roll along each exterior top side of the bobsleigh. These vortices may form high rotational velocity/low pressure delta wing vortices at each side edge of the cowling that sucks air out of the open cowling and creates a pressure drop inside the cowling.…”

“…These vortices may form high rotational velocity/low pressure delta wing vortices at each side edge of the cowling that sucks air out of the open cowling and creates a pressure drop inside the cowling. [49][50][51][64][65][66] Several authors have suggested that having the brake person lean forward approximately 45°-55°(from the vertical) will reduce 2-person or 4-person bobsleigh drag by 3.5% to 6%, as compared to an upright torso position. [48][49][50][65][66][67] The forward lean reduces the lowpressure area behind the pilot and reduces turbulence created by the brake person's helmet.…”

Automation of the aerodynamic shape development process of bobsleigh components

“…Motallebi, Dabnichki, and Luck (2004) and Dabnichki and Avital (2006) conducted numerical simulations and wind tunnel experiments in order to improve single bobsleigh components as well as the posture of the bobsleigh crew. Winkler & Pernpeintner (2008) showed that the aerodynamic drag of a bobsleigh can be reduced by about 13% when applying the currently prevailing aerodynamic development process systematically including both computational and experimental tools.…”