Cyclist Reynolds number effects and drag crisis distribution
| Autor: | W. Terra, Fulvio Scarano, Andrea Sciacchitano |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Drag coefficient
010504 meteorology & atmospheric sciences Cycling aerodynamics Drag crisis Wake 01 natural sciences 010305 fluids & plasmas Reynolds number symbols.namesake Wind tunnel testing 0103 physical sciences 0105 earth and related environmental sciences Civil and Structural Engineering Physics Renewable Energy Sustainability and the Environment Mechanical Engineering Mechanics Critical ionization velocity Particle image velocimetry body regions Drag symbols Freestream |
| Zdroj: | Journal of Wind Engineering & Industrial Aerodynamics, 200 |
| ISSN: | 0167-6105 |
| Popis: | 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 parts, but also by the presence of coherent streamwise vortical structures. Moreover, the interaction with the wakes of the upstream body parts plays a role in the local wake properties. While reductions of the wake width are observed on both lower leg and arm with increasing free-stream velocity, the wake of the upper leg follows an opposite trend increasing in size at higher velocity. Such variations of wake width with the Reynolds number are related to the behaviour of the local drag coefficient, indicating a drag crisis behaviour on both leg and arm. The distribution of the so-called critical velocity upon these body segments is discussed, as it determines the freestream speed where a minimum value for the drag can occur. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect