Cyclists use to wear different helmets and adopt different body positions on the bicycle to minimize resistance. The aim of this study was to compare a standard helmet with the new aero road helmets in a bicycle-cyclist system by CFD on the dropped position. An elite level road cyclist volunteered to this research. The cyclist was scanned on his racing bicycle on the dropped position wearing competition gear and a standard helmet and an aero road helmet. A three-dimensional domain around the cyclist with 7 m of length, 2.5 m of width and 2.5 m of height and meshed with more than 43 million of prismatic and tetrahedral elements. The numerical simulations were conducted at 11.11 m/s. The numerical simulations outputs were viscous, pressure and total drag and coefficient of drag. The standard helmet presented a viscous drag of 10.52 N, a pressure drag of 16.51 N and a total drag of 21.98 N. The aero road helmet presented a pressure drag of 7.40 N, a viscous drag of 12.56 N and a total drag of 19.96 N. Moreover, the aero road helmet presented a lower viscous, pressure and total drag coefficient in comparison to the standard helmet. It is possible to conclude that an aero road helmet imposes less drag in comparison to a standard helmet.
Citation: Pedro Forte, Daniel A Marinho, Tiago M Barbosa, Jorge E Morais. Analysis of a normal and aero helmet on an elite cyclist in the dropped position[J]. AIMS Biophysics, 2020, 7(1): 54-64. doi: 10.3934/biophy.2020005
Cyclists use to wear different helmets and adopt different body positions on the bicycle to minimize resistance. The aim of this study was to compare a standard helmet with the new aero road helmets in a bicycle-cyclist system by CFD on the dropped position. An elite level road cyclist volunteered to this research. The cyclist was scanned on his racing bicycle on the dropped position wearing competition gear and a standard helmet and an aero road helmet. A three-dimensional domain around the cyclist with 7 m of length, 2.5 m of width and 2.5 m of height and meshed with more than 43 million of prismatic and tetrahedral elements. The numerical simulations were conducted at 11.11 m/s. The numerical simulations outputs were viscous, pressure and total drag and coefficient of drag. The standard helmet presented a viscous drag of 10.52 N, a pressure drag of 16.51 N and a total drag of 21.98 N. The aero road helmet presented a pressure drag of 7.40 N, a viscous drag of 12.56 N and a total drag of 19.96 N. Moreover, the aero road helmet presented a lower viscous, pressure and total drag coefficient in comparison to the standard helmet. It is possible to conclude that an aero road helmet imposes less drag in comparison to a standard helmet.
| [1] | Barbosa TM, Forte P, Morais JE, et al. (2016) Analysis of the aerodynamics by experimental testing of an elite wheelchair sprinter. 11th conference of the International Sports Engineering Association, Elsevier 147: 2-6. |
| [2] |
Barelle C, Chabroux V, Favier D (2010) Modeling of the time trial cyclist projected frontal area incorporating anthropometric, postural and helmet characteristics. Sport Eng 12: 199-206. doi: 10.1007/s12283-010-0047-y
|
| [3] |
Beaumont F, Taiar R, Polidori G, et al. (2018) Aerodynamic study of time-trial helmets in cycling racing using CFD analysis. J Biomech 67: 1-8. doi: 10.1016/j.jbiomech.2017.10.042
|
| [4] |
Defraeye T, Blocken B, Koninckx E, et al. (2010) Aerodynamic study of different cyclist positions: CFD analysis and full-scale wind-tunnel tests. J Biomech 43: 1262-1268. doi: 10.1016/j.jbiomech.2010.01.025
|
| [5] |
Gross AC, Kyle CR, Malewicki DJ (1983) The aerodynamics of human-powered land vehicles. Sci Am 249: 142-153. doi: 10.1038/scientificamerican1283-142
|
| [6] | Kyle CR, Burke E (1984) Improving the racing bicycle. Mech Eng 106: 34-45. |
| [7] |
Blocken B, van Druenen T, Toparlar Y, et al. (2018) Aerodynamic analysis of different cyclist hill descent positions. J Wind Eng Ind Aerod 181: 27-45. doi: 10.1016/j.jweia.2018.08.010
|
| [8] |
Underwood L, Schumacher J, Burette-Pommay J, et al. (2011) Aerodynamic drag and biomechanical power of a track cyclist as a function of shoulder and torso angles. Sport Eng 14: 147-154. doi: 10.1007/s12283-011-0078-z
|
| [9] | Kyle CR (1996) Selecting cycling equipment. High-tech cycling Champaign, Illinois: Human Kinetics, 1-48. |
| [10] | Burke ER, Pruitt AL (2003) Body positioning for cycling. High-tech cycling, 2 Eds Champaign, Illinois: Human Kinetics, 69-92. |
| [11] |
Fintelman DM, Sterling M, Hemida H, et al. (2014) Optimal cycling time trial position models: Aerodynamics versus power output and metabolic energy. J Biomech 47: 1894-1898. doi: 10.1016/j.jbiomech.2014.02.029
|
| [12] | Forte P, Barbosa TM, Marinho DA (2015) Technologic appliance and performance concerns in wheelchair racing–helping Paralympic athletes to excel. New Perspectives in Fluid Dynamics Rijeka, Croatia: IntechOpen, 101-121. |
| [13] |
Forte P, Marinho DA, Morais JE, et al. (2018) The variations on the aerodynamics of a world-ranked wheelchair sprinter in the key-moments of the stroke cycle: A numerical simulation analysis. PloS One 13: e0193658. doi: 10.1371/journal.pone.0193658
|
| [14] |
Brühwiler PA, Buyan M, Huber R, et al. (2006) Heat transfer variations of bicycle helmets. J Sport Sci 24: 999-1011. doi: 10.1080/02640410500457877
|
| [15] |
Forte P, Marinho DA, Morouço P, et al. (2017) Comparison by computer fluid dynamics of the drag force acting upon two helmets for wheelchair racers. AIP Conference Proceedings AIP Publishing LLC, 520005. doi: 10.1063/1.4992669
|
| [16] |
Blocken B, Defraeye T, Koninckx E, et al. (2013) CFD simulations of the aerodynamic drag of two drafting cyclists. Comput Fluids 71: 435-445. doi: 10.1016/j.compfluid.2012.11.012
|
| [17] |
El Helou N, Berthelot G, Thibault V, et al. (2010) Tour de France, Giro, Vuelta, and classic European races show a unique progression of road cycling speed in the last 20 years. J Sport Sci 28: 789-796. doi: 10.1080/02640411003739654
|
| [18] | Aroussi A, Kucukgokoglan S, Pickering SJ, et al. (2001) Evaluation of four turbulence models in the interaction of multi burners swirling flows. 4th International Conference On Multiphase Flow . |
| [19] |
Blocken B, Toparlar Y (2015) A following car influences cyclist drag: CFD simulations and wind tunnel measurements. J Wind Eng Ind Aerod 145: 178-186. doi: 10.1016/j.jweia.2015.06.015
|
| [20] |
Defraeye T, Blocken B, Koninckx E, et al. (2010) Aerodynamic study of different cyclist positions: CFD analysis and full-scale wind-tunnel tests. J Biomech 43: 1262-1268. doi: 10.1016/j.jbiomech.2010.01.025
|
| [21] |
Forte P, Marinho DA, Morouço P, et al. (2017) Comparison by computer fluid dynamics of the drag force acting upon two helmets for wheelchair racers. AIP Conference Proceedings AIP Publishing LLC, 520005. doi: 10.1063/1.4992669
|
| [22] | Brownlie L, Ostafichuk P, Tews E, et al. (2010) The wind-averaged aerodynamic drag of competitive time trial cycling helmets. Procedia Eng 2: 2419C2424. |
| [23] |
Pugh LGCE (1971) The influence of wind resistance in running and walking and the mechanical efficiency of work against horizontal or vertical forces. J Physiol 213: 255-276. doi: 10.1113/jphysiol.1971.sp009381
|
| [24] |
Debraux P, Grappe F, Manolova AV, et al. (2011) Aerodynamic drag in cycling: methods of assessment. Sport Biomech 10: 197-218. doi: 10.1080/14763141.2011.592209
|
| [25] | Schlichting H, Gersten K (1979) Boundary-Layer Theory New York: MacGraw Hill. |
| [26] | Abdullah MN, Muda MKH, Mustapha F, et al. (2017) Aerodynamics analysis for an outdoor road cycling helmet and air attack helmet. Int J Mater Mech Manuf 5: 46-50. |
Figures(6)
Pedro Forte, Daniel A Marinho, Tiago M Barbosa, Jorge E Morais. Analysis of a normal and aero helmet on an elite cyclist in the dropped position[J]. AIMS Biophysics, 2020, 7(1): 54-64. doi: 10.3934/biophy.2020005
DownLoad: