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. 2008 Mar 1;7(1):60-6.
eCollection 2008.

Analysis of drafting effects in swimming using computational fluid dynamics

António José Silva, Abel Rouboa, António Moreira, Victor Machado Reis, Francisco Alves, João Paulo Vilas-Boas, Daniel Almeida Marinho

Analysis of drafting effects in swimming using computational fluid dynamics

António José Silva et al. J Sports Sci Med. .

Abstract

The purpose of this study was to determine the effect of drafting distance on the drag coefficient in swimming. A k-epsilon turbulent model was implemented in the commercial code Fluent(®) and applied to the fluid flow around two swimmers in a drafting situation. Numerical simulations were conducted for various distances between swimmers (0.5-8.0 m) and swimming velocities (1.6-2.0 m.s(-1)). Drag coefficient (Cd) was computed for each one of the distances and velocities. We found that the drag coefficient of the leading swimmer decreased as the flow velocity increased. The relative drag coefficient of the back swimmer was lower (about 56% of the leading swimmer) for the smallest inter-swimmer distance (0.5 m). This value increased progressively until the distance between swimmers reached 6.0 m, where the relative drag coefficient of the back swimmer was about 84% of the leading swimmer. The results indicated that the Cd of the back swimmer was equal to that of the leading swimmer at distances ranging from 6.45 to 8. 90 m. We conclude that these distances allow the swimmers to be in the same hydrodynamic conditions during training and competitions. Key pointsThe drag coefficient of the leading swimmer decreased as the flow velocity increased.The relative drag coefficient of the back swimmer was least (about 56% of the leading swimmer) for the smallest inter-swimmer distance (0.5 m).The drag coefficient values of both swimmers in drafting were equal to distances ranging between 6.45 m and 8.90 m, considering the different flow velocities.The numerical simulation techniques could be a good approach to enable the analysis of the fluid forces around objects in water, as it happens in swimming.

Keywords: Training; drag; finite element modeling; human body; tandem.

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Figures

Figure 1.
Figure 1.
Boundary conditions.
Figure 2.
Figure 2.
Mesh with a 0.05 spacing in drafting swimming. Distance between swimmers equal to 0.5 m.
Figure 3.
Figure 3.
Pressure profile in drafting swimming. Distance between swimmers equal to 0.5 m. Flow velocity equal to 2.0 m·.s-1.
Figure 4.
Figure 4.
Percentual relation between the leading swimmer Cd (Cd1) and the back swimmer Cd (Cd2) for velocities of 1.60, 1.80 and 2.00 m·s-1.
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References

    1. Alves F., Marinho D., Leal L., Rouboa A., Silva A. (2007) 3-D computational fluid dynamics of the hand and forearm in swimming. Medicine and Science in Sports and Exercise 39(Suppl. 1), S9
    1. Bassett D.R., Flohr J., Duey W.J., Howley E.T., Pein R.L. (1991) Metabolic responses to drafting during front crawl swimming. Medicine and Science in Sports and Exercise 23(6), 744-747 - PubMed
    1. Berthier B., Bouzerar R., Legallais L. (2002) Blood flow patterns in an automatically realistic coronary vessel: influence of three different reconstruction methods. Journal of Biomechanics 35(10), 1347-1356 - PubMed
    1. Bixler B.S., Riewald S. (2002) Analysis of swimmer’s hand and arm in steady flow conditions using computational fluid dynamics. Journal of Biomechanics 35(5), 713-717 - PubMed
    1. Bixler B.S., Schloder M. (1996) Computational fluid dynamics: an analytical tool for the 21st century swimming scientist. Journal of Swimming Research 11(1), 4-22

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