Modeling of Wheel Aerodynamics and its Impact on Cycling

Name: Fabio Malizia

When: 08/09/2020 17:00
Language: en

• When: 08.09.2020, 17h00
• Language: English
• Where: aula van de Tweede Hoofdwet, 01.02, Kasteelpark Arenberg 41, 3001 Heverlee

• Prof. dr. ir. Bert Blocken (promotor)
• De heer Hamid Montazeri (co-promotor)

There are many aspects to consider when analysing the performance of a cyclist, but ultimately, what matters for the cyclist is to win the race. Professional cyclists might win the race by very small margins. For example LeMond won the 1989 Tour de France in 87h38'35", only 8" ahead of Fignon. The question is then how to provide enough competitive advantages to professional cyclists to help them win the race. It is known that the major force opposing the cyclist motion on a flat terrain and at high speed is the aerodynamic drag, thus the resistance caused by the movement of the cyclist in the air.

Researchers and manufacturers are studying ways to improve the movement of the cyclist and the bicycle in the air. One of the components that has been produced in many variants is the wheel, because there are many manufacturers active in the market. Common practice to reduce the wheel’s drag is to decrease the number of spokes, to use deeper rims and to properly select the ratio between the tire width and the rim width. The new wheel models can be physically tested inside a wind tunnel once a model is created, or their aerodynamics can be virtually tested using computer simulations, also called computational fluid dynamics (CFD) simulations. CFD simulations and/or wind tunnel tests need to be very accurate to correctly predict the forces and moments acting on the wheel: this is needed to correctly assess which wheel has the lowest drag, so the cyclists can gain precious seconds.

My PhD first discusses cycling aerodynamics as a whole, considering the evolution in cycling equipment from an aerodynamic point of view. Then it focuses on the isolated wheel, creating a set of guidelines for CFD simulations that should be followed to obtain reliable and accurate aerodynamic results for the wheel with spokes. Finally, the influence of a front sixteen-spokes wheel on the aerodynamic performance of the combined bicycle-cyclist system is assessed. The information provided in the thesis will help manufacturers to better assess the wheel aerodynamics thus to further improve its performance, and thereby also the cyclist performance.

https://lirias.kuleuven.be/handle/123456789/658923

• Prof. dr. ir. Bert Blocken (promotor)
• De heer Hamid Montazeri (co-promotor)
• Prof. dr. ir. Omer Van der Biest (chairman)
• De heer Twan Antonius Johannes van Hooff (secretary)
• Prof. dr. Johan Meyers
• Prof. dr. ir. Bart Nicolai
• Dr. Frédéric Grappe , Université de Bourgogne-Franche-Comté
• Dr. Eoghan Clifford , National University of Ireland Galwa