Aerodynamic drag determination of a full-scale cyclist mannequin from largescale PTV measurements

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Abstract

Large-scale Particle Tracking Velocimetry (PTV) measurements are cond ucted in the wake of a fu ll-scale cyclist model in time-trial position at freestream velocities between 12.5 and 15 m/ s, corresponding to Reynolds numbers of the order of 5×105. Lagrangian particle tracking is employed to determine the velocity and static pressure statistics in the wake plane, showing good agreement with previous results reported in literature. The aerodynamic drag is estimated from the large-scale PTV measurements invoking the conservation of momentum in a control volume enclosing the model (PIV wake rake approach). The estimated drag follows the expected quadratic increase with increasing freestream velocity. The accuracy of the drag estimate is evaluated by comparison to state-of-the-art force balance measurements, resulting in a resolution of the PIV wake rake approach of 30 drag counts. The three terms composing the overall drag force, associated with the time-average streamwise velocity, its fluctuations and the time-averaged pressure, respectively, are evaluated separately, demonstrating that the contribution of the pressure term is negligible and the resistive force is dominated by the time-average streamwise momentum deficit.
Original languageEnglish
Title of host publicationProceedings of the 19th international symposium on application of laser and imaging techniques to fluid mechanics
Number of pages18
Publication statusPublished - 2018
EventLXLASER2018: 19th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics - Lisbon, Portugal
Duration: 16 Jul 201819 Jul 2018
Conference number: 19
http://www.lisbon-lasersymposium.org/LXLASER2018

Conference

ConferenceLXLASER2018: 19th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics
Abbreviated titleLXLASER2018
CountryPortugal
CityLisbon
Period16/07/1819/07/18
Internet address

Keywords

  • Aerodynamic drag
  • PIV wake rake
  • human-scale PTV
  • helium-filled soap bubbles
  • cycling aerodynamics

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