The Power of PeopleIn transportation, some of the most ecofriendly forms of travel involve the power of the human body, such as rowing, walking, running and cycling. Turn-ing human activity into high speeds is challenging. Students around the world participate in the World Human Powered Speed Challenge in an attempt to break the world speed record for males (86.65 mph) and females (75.69 mph). The University of Liverpool Velocipede Team (ULVT) employs engineering simulation from ANSYS in the design of its highly aerodynamic bike, ARION1.

Sponsored by Rathbone Investment Management and supported by Friends of the University of Liverpool, the students developed and manufactured a monoco-que design incorporating a carbon-fiber shell into the structure of the bike. At 80 mph, 70 percent of the retarding forces acting upon the bike result from drag upon the shell, so aerodynamic optimization is critical to a successful world record attempt. To minimize drag they needed to delay the transition to a turbulent flow regime along the sides of the shell for the high Reynolds numbers at which the vehicle operates. The undergraduate student team had just one year to learn to mesh, compute and interpret CFD data, so it was essential to obtain information early in the bike design process be-fore the outer shell design was frozen for manufacture.

Employing the easy-to-use ANSYS CFD software with the transition-SST turbulence model, the team made rapid

progress and obtained results that compared favorably with wind tunnel data. This allowed them to make appropriate changes to the monocoque to reduce drag, while ensuring appropriate downforce at the front end of the bike. The team will be using ANSYS software to optimize the shell aerodynamically for the third version of the bike in 2017, and hopes to challenge the hand-powered land speed record at the same event.Information courtesy Toby Dafforn-Jones, Michael Francis Kelly and Mark D. White.

ACADEMIC

^ANSYS mesh of ARION1

^ Wind tunnel testing of ARION1 for validation of CFD approach

“ Aerodynamic optimization is critical to a successful world record attempt.”

ARION1 human-powered vehicle >