On-site cycling drag analysis with the Ring of Fire

Spoelstra, Alexander; Norante, Luigi de Martino; Terra, Wouter; Sciacchitano, Andrea; Scarano, Fulvio

doi:10.1007/s00348-019-2737-y

Cited by 22 publications

(29 citation statements)

References 50 publications

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“…Furthermore, the rider transited the laser sheet with no predefined crank-angle, meaning that the crank-angle at the laser sheet location varied from run to run. The uncertainties of the drag area measurements are similar to those reported for previous RoF experiments, namely below 5% [9]. The drag of the drafting cyclist varies significantly as a function of his position with respect to the lead cyclist (see Figure 3 below).…”

Section: Resultssupporting

confidence: 81%

“…Time resolved stereo-PIV measurements are conducted to determine the drafting effect on cyclists when they ride behind a lead cyclist. The conservation of momentum in a control volume is adapted from [9] to determine the individual athletes' aerodynamic drag. Within the measured spectrum, the savings for the drafting cyclist range from 27% to 66%.…”

Section: Discussionmentioning

confidence: 99%

“…The drag evaluation through the Ring of Fire follows those of previous investigations [9]. The instantaneous drag force D(t) is evaluated by invoking the conservation of momentum expressed in a control volume around a cyclist.…”

Section: Methodsmentioning

confidence: 99%

“…In the recent years, a measurement concept has been introduced by the authors, named the Ring of Fire (RoF) ( [9]). The concept is based on large-scale stereoscopic particle image velocimetry (PIV) measurements in quiescent air where an object or a vehicle travels through it.…”

Section: Introductionmentioning

confidence: 99%

“…The analysis of the momentum difference between the conditions prior to and after the passage poses the basis to estimate the aerodynamic drag. The measurement system was shown to provide the aerodynamic drag of an individual cyclist during sport action and returned a quantitative visualization of the flow field in the wake [9]. Thanks to the ability to measure the flow field in the wake of a cyclist, as well as the posture and the relative distances between riders, the Ring of Fire system is in principle suitable for the investigation of the aerodynamics of a group of riders.…”

Section: Introductionmentioning

confidence: 99%

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Drafting Effect in Cycling: On-Site Aerodynamic Investigation by the ‘Ring of Fire’

Spoelstra

Mahalingesh

Sciacchitano

2020

The 13th Conference of the International Sports Engineering Association

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An on-site Ring of Fire (RoF) experiment is performed at the Tom Dumoulin bike park in Sittard-Geleen, the Netherlands. The current work investigates the aerodynamic drag of a cyclist following a lead cyclist at different lateral and longitudinal separations; additionally, the athletes’ skills to maintain their position and distance with respect to the preceding riders are evaluated. The effect of the relative size of the lead cyclist on the drag area of the drafting cyclist is also investigated. The results show drag reductions of the trailing cyclist in the range from 27% to 66% depending on the longitudinal and lateral separation from the leading rider. The aerodynamic advantage of the drafting rider decreases with increasing lateral and longitudinal separation between riders, with the lateral separation found to be more relevant. Besides this, the drag reduction of the drafting cyclist benefits from an increase in drag area of the leading cyclist.

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Section: Resultssupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Drafting Effect in Cycling: On-Site Aerodynamic Investigation by the ‘Ring of Fire’

Spoelstra

Mahalingesh

Sciacchitano

2020

The 13th Conference of the International Sports Engineering Association

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Effects of Wheel Depth on Individual Time Trial Performance Among Skilled Cyclists

Nabil,

Hasan,

Ismail

et al. 2023

Proceedings of the 8th International Conference on Movement, Health and Exercise

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The slip velocity of nearly neutrally buoyant tracers for large-scale PIV

Faleiros

Tuinstra²,

Sciacchitano

et al. 2021

Exp Fluids

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The behaviour of nearly neutrally buoyant tracers is studied by means of experiments with helium-filled soap bubbles and numerical simulations. The current models used for estimating the slip velocity of heavy micro particles and neutrally buoyant particles are reviewed and extended to include the effect of unsteady forces and particle Reynolds number. The particle motion is analysed via numerical simulations of a rectilinear oscillatory flow and in the flow around an airfoil within a particle flow parameter space that is typical of large-scale PIV experiments. An empirical relation is obtained that estimates the particle slip velocity, depending on the particle-to-fluid density ratio, the particle Reynolds number and frequency of the local flow fluctuations. The model developed is applied to assess the slip velocity of helium-filled soap bubbles in a large-scale experiment conducted at the German–Dutch wind (DNW) tunnels in the flow around an airfoil, with chord Reynolds numbers up to three millions. Furthermore, a procedure is proposed that can be used to retrieve the bubbles mean density and dispersion from measurements of mean velocity and fluctuations, respectively. Graphic abstract

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On-site cycling drag analysis with the Ring of Fire

Abstract: The Ring of Fire (RoF) measurement concept, introduced by Terra et al. (Exp Fluids 58:83.

Cited by 22 publications

References 50 publications

Drafting Effect in Cycling: On-Site Aerodynamic Investigation by the ‘Ring of Fire’

Drafting Effect in Cycling: On-Site Aerodynamic Investigation by the ‘Ring of Fire’

Effects of Wheel Depth on Individual Time Trial Performance Among Skilled Cyclists

The slip velocity of nearly neutrally buoyant tracers for large-scale PIV

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