Cyclist Drag Reduction through the Manipulation of the 3D Flow Topology: An investigation by means of numerical simulations and robotic volumetric PTV

The importance of aerodynamic efficiency in the cycling sport is well known. Simple calculations demonstrate the considerable impact of just a few percentages in drag savings on the outcome of a competition where the margins can be incredibly small. Achieving a drag reduction can, however, be challenging as the flow topology of a cyclist is...

Drag reduction of bluff bodies in tandem: Size and spacing effects on cylinders and cyclists

In cycling, the presence of drag reduction from drafting, when multiple cyclists ride in tandem, is a considerable area of performance enhancement for a cycling team and the customisation of this tandem group has the potential of maximising the drag reduction for the entire group or a specific cyclist. The flow interactions between two tandem...

Cyclist Mannequin For Aerodynamics Research: Develop a cyclist mannequin from 3D scans for aerodynamics tests.

The aim of this research is to increase the speed of cyclists by reducing aerodynamic drag. Common research methods are digital and physical simulations. The goal is this project is to develop an anthropometric model for each method based on professional cyclists from Team DSM.<br/><br/>Digital Model (Generic)<br/>The first goal of this research...

Ring of fire as a novel approach to study cycling aerodynamics

The research presented in this thesis introduces a new measurement concept for on-site aerodynamic measurements based on large-scale stereoscopic particle image velocimetry (stereo-PIV) measurements past an athlete, a vehicle or an object travelling through a quiescent environment. The analysis of the momentumdeficit past the transit poses the...

Aerodynamics of a cycling wheel in crosswind by coaxial volumetric velocimetry

The aerodynamic characteristics of a modern road cycling wheel in crosswind are studied through force measurements and 3D velocimetry in TU Delft’s Open Jet Facility. The performance of the 62 mm deep rim is evaluated for two tire profiles, and yaw angles up to 20◦ . All measurements are executed at 12.5 m/s (45 km/h) freestream- and wheel...

Cyclist Aerodynamic Drag Analysis through Large-Scale PIV

The use of large-scale particle image velocimetry (PIV) is proposed for cycling aerodynamic study to advance the general understanding of the flow around the rider and the bike, leading to new strategies for cycling aerodynamic drag reduction in the future. The investigation concentrates on the measurement of the wake velocity and its relation...

Cyclist Reynolds number effects and drag crisis distribution

The Reynolds number effects on body limbs of a cyclist model, namely leg and arm, are investigated via robotic volumetric Particle Image Velocimetry measurements in the velocity range from 5 ​m/s to 25 ​m/s. The near wakes of such body limbs feature recirculation regions whose width and length are governed not only by the taper of the body...

On-site drafting aerodynamics of cyclists using the Ring of Fire

Aerodynamics plays a significant role in the field of cycling as it is the dominant resistive force at racing speeds of 50 km/h. Sporting events involving multiple cyclists leads to aerodynamic interactions between the cyclists and these interactions have been exploited for performance benefits. One such aerodynamic interaction is drafting,...

Uncertainty assessment of the Ring of Fire concept for on-site aerodynamic drag evaluation

The Ring of Fire (RoF) measurement concept to perform on-site experiments of aerodynamic drag for transiting objects is investigated with a study that identifies the main sources of uncertainty. The main contributors to the uncertainty of the drag measurement are examined for the case of a cyclist riding through the measurement domain. A...

Accuracy assessment of the Ring of Fire system for on-site aerodynamic drag measurements

The continuous pursuit of reducing drag in many speed sports, such as cycling and ice-skating, demands novel approaches to gain further insight into flow phenomena around athletes. In recent years, the Ring of Fire measurement technique has emerged as a feasible option to visualise and analyse flow structures of transiting objects based on...

Advances and assessment of the Ring of Fire concept for on-site cycling aerodynamics

Aerodynamics investigations in speed sports generally consist of measurements of aerodynamic loads through wind tunnel experiments. Lately, a new technique has emerged, known as the Ring of Fire. It is the only drag measurement technique capable of retrieving flow field data on-site, by using Large-Scale PIV. In this Ring-of-Fire project a Low...

Robotic Volumetric Particle Tracking Velocimetry by Coaxial Imaging and Illumination

Aerodynamics research and development often involves large-scale and turbulent flows; may this be a rotor flow, the wake of a car, or the flow passing a human athlete to name a few examples. Volumetric particle image velocimetry (PIV) is well suited for the study of such flows. The introduction of Helium Filled Soap Bubbles (HFSB) for wind...