Aerodynamic study of time-trial helmets in cycling racing using CFD analysis

Beaumont, Fabien; Taı̈ar, Redha; Polidori, Guillaume; Trenchard, Hugh; Grappe, Frédéric

doi:10.1016/j.jbiomech.2017.10.042

Cited by 41 publications

(38 citation statements)

References 22 publications

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“…In Olympic races, cyclists mean speed is near 40 km/h (11.11 m/s) (El Helou et al, 2010). It is possible to find in the literature ACd values between 0.261 and 0.42 m 2 (Zdravkovic et al, 1996;Grappe et al, 1997;Candau et al, 1999;Defraeye et al, 2010a;Beaumont et al, 2018). It is expected that in the same conditions as in our study, drag reported in the literature varies between 0.16 and 131.32 N, in a range of speeds from 1 to 22 m/s.…”

Section: Discussionmentioning

confidence: 99%

“…D is the main RF in cycling and is related with the cyclist positions and increases with speed (Gross et al, 1983;Kyle and Burke, 1984;Defraeye et al, 2010a;Debraux et al, 2011). The effective surface area (ACd) results from the multiplication of surface area (A) and coefficient of drag (Cd) (Forte et al, 2015(Forte et al, , 2018b and it is a mainstream procedure to assess cyclists' aerodynamics (Zdravkovic et al, 1996;Grappe et al, 1997;Candau et al, 1999;Defraeye et al, 2010a;Beaumont et al, 2018). Positions with smaller surface areas may also lead to less D. However, the body shape and equipment's design may affect the fluid flow and aerodynamics (Schlichting and Gersten, 2016).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Estimation of an Elite Road Cyclist Performance in Different Positions Based on Numerical Simulations and Analytical Procedures

Forte¹,

Marinho

Barbosa

et al. 2020

Front. Bioeng. Biotechnol.

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The aim of this study was to use numerical simulations and analytical procedures to compare a cyclist's performance in three different cycling positions. An elite level road cyclist competing at a national level was recruited for this research. The bicycle was 7 kg and the cyclist 55 kg. A 3D scan was taken of the subject on the competition bicycle, wearing race gear and helmet in the upright position, in the handlebar drops (dropped position) and leaning on the elbows (elbows position). Numerical simulations by computer fluid dynamics in Fluent CFD code assessed the coefficient of drag at 11.11 m/s. Following that, a set of assumptions were employed to assess cycling performance from 1 to 22 m/s. Drag values ranged between 0.16 and 99.51 N across the different speeds and positions. The cyclist mechanical power in the elbows position differed from the upright position between 0 and 23% and from the dropped position from 0 to 21%. The cyclist's energy cost in the upright position differed 2 to 16% in comparison to the elbows position and the elbows position had less 2 to 14% energy cost in comparison to the dropped position. The estimated time of arrival was computed for a 220,000 m distance and it varied between 7,715.03 s (2 h:8 min:24 s) and 220,000 s (61 h:6 min:40 s) across the different speeds and positions. In the elbows position, is expected that a cyclist may improve the winning time up to 23% in comparison to he upright and dropped position across the studied speeds.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Estimation of an Elite Road Cyclist Performance in Different Positions Based on Numerical Simulations and Analytical Procedures

Forte¹,

Marinho

Barbosa

et al. 2020

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

show abstract

“…Indeed, the concepts, methods, and analytical techniques that we use to characterize human mechanics represent major economic stakes. The development is necessarily inscribed in a vision of interactions between the physical sciences (metrology, complex mechanical and electronic systems), information sciences and technologies, and life sciences (materials, tissues, organs, and limbs) [3][4][5][6][7][8]. The ambition of the research work carried out in biomechanics is to improve the performance of high-level athletes and the comfort and quality of life of patients and to minimize stress on joints in real-field or laboratory situations.…”

Section: The Concepts and Basis Of Biomechanicsmentioning

confidence: 99%

Introductory Chapter: Biomechanics, Concepts and Knowledge

Taı̈ar¹

2020

Recent Advances in Biomechanics

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“…[6][7][8][9][10][11]) and the associated flow topologies [12][13][14], the bicycle and bicycle components [5,[15][16][17], wearable equipment such as helmets (e.g. [18,19]) and the interaction between drafting cyclists [20][21][22][23][24][25]. Together with previous studies, these efforts have led to more and better insights in the aerodynamics of cycling.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic benefits for a cyclist by drafting behind a motorcycle

et al. 2020

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Motorcycles are present in cycling races for reasons including television broadcasting. During parts of the race, these motorcycles ride in front of individual or groups of cyclists. Concerns have been expressed in the professional cycling community that these motorcycles can provide aerodynamic benefits in terms of drag reduction for the cyclists drafting behind them. However, to the best of our knowledge, no information about the extent of these benefits is present in the scientific literature. Therefore, this paper analyses the potential drag reduction for a cyclist by drafting behind a motorcycle. Wind tunnel measurements and numerical simulations with computational fluid dynamics were performed. It was shown that drafting at separation distances d = 2.64, 10, 30 and 50 m can reduce the drag of the cyclist down to 52, 77, 88 and 93% of that of an isolated cyclist, respectively. A cyclist power model is used to convert these drag reductions into potential time gains. For a non-drafting cyclist at a speed of 54 km/h on level road in calm weather, the time gains by drafting at d = 2.64, 10, 30 and 50 m are 12.7, 5.4, 2.7 and 1.6 s per km, respectively. These time differences can influence the outcome of cycling races. The current rules of the International Cycling Union do not prevent these aerodynamic benefits from occurring in races.

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Aerodynamic study of time-trial helmets in cycling racing using CFD analysis

Cited by 41 publications

References 22 publications

Estimation of an Elite Road Cyclist Performance in Different Positions Based on Numerical Simulations and Analytical Procedures

Estimation of an Elite Road Cyclist Performance in Different Positions Based on Numerical Simulations and Analytical Procedures

Introductory Chapter: Biomechanics, Concepts and Knowledge

Aerodynamic benefits for a cyclist by drafting behind a motorcycle

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