Percorrer por autor "Mantripragada, Narendra"
A mostrar 1 - 4 de 4
Resultados por página
Opções de ordenação
- Modelling hydrodynamic drag in swimming using computational fluid dynamicsPublication . Marinho, D.A.; Barbosa, Tiago M.; Kjendlie, Per L.; Mantripragada, Narendra; Vilas-Boas, João Paulo; Machado, Leandro; Alves, Francisco B.; Rouboa, Abel; Silva, A.J.In the sports field, numerical simulation techniques have been shown to provide useful information about performance and to play an important role as a complementary tool to physical experiments. Indeed, this methodology has produced significant improvements in equipment design and technique prescription in different sports (Kellar et al., 1999; Pallis et al., 2000; Dabnichki & Avital, 2006). In swimming, this methodology has been applied in order to better understand swimming performance. Thus, the numerical techniques have been addressed to study the propulsive forces generated by the propelling segments (Rouboa et al., 2006; Marinho et al., 2009a) and the hydrodynamic drag forces resisting forward motion (Silva et al., 2008; Marinho et al., 2009b). Although the swimmer’s performance is dependent on both drag and propulsive forces, within this chapter the focus is only on the analysis of the hydrodynamic drag. Therefore, this chapter covers topics in swimming drag simulation from a computational fluid dynamics (CFD) perspective. This perspective means emphasis on the fluid mechanics and CFD methodology applied in swimming research. One of the main aims for performance (velocity) enhancement of swimming is to minimize drag forces resisting forward motion, for a given trust. This chapter will concentrate on numerical simulation results, considering the scientific simulation point-of-view, for this practical implication in swimming. In the first part of the chapter, we introduce the issue, the main aims of the chapter and a brief explanation of the CFD methodology. Then, the contribution of different studies for swimming using CFD and some practical applications of this methodology are presented. During the chapter the authors will attempt to present the CFD data and to address some practical concerns to swimmers and coaches, comparing as well the numerical data with other experimental data available in the literature.
- The effect of depth on drag during the gliding phase in swimmingPublication . Marinho, D.A.; Ribeiro, João; Mantripragada, Narendra; Machado, Leandro; Vilas-Boas, João Paulo; Fernandes, Ricardo J.; Barbosa, Tiago M.; Rouboa, Abel; Silva, A.J.The gliding phase following a swimming start or turn is an important component of the overall swimming performance. PURPOSE: To analyse the effect of depth on hydrodynamic drag force during the underwater gliding, using computational fluid dynamics. METHODS: A three-dimensional domain was created to simulate the fluid flow around a swimmer model, representing the geometry of part of a lane in a swimming pool. The water depth of this domain was 1.50 m with a 3.0 m width and 11.0 m length. Computational fluid dynamics methodology was used to perform numerical simulations in the created domain which was divided into a number of mesh cells. The k-epsilon turbulent model was applied to the flow around a three-dimensional model of a male adult swimmer in a prone gliding position with the arms extended at the front. General moving object model was used to simulating the body as the displacing object. During the gliding, the swimmer model’s middle line was placed at three different water depths: at 0.20 m (just under the surface), at 0.75 m (middle of the pool), and at 1.30 m (bottom of the pool). The drag coefficient and the hydrodynamic drag force were computed using a steady velocity of 2.50 m/s for the different depths run for 3 s in each case. RESULTS: The drag coefficient was 0.37, 0.34 and 0.30 and the drag force was 141.40 N, 128.10 N and 115.30 N when gliding at a water depth of 0.20 m, 0.75 m and 1.30 m, respectively, at the time of 2 s when the swimmer was approximately at the middle of the computational pool. CONCLUSIONS: The hydrodynamic drag values for the gliding decreased with the increase in depth. This decrease of drag values with depth can be due to the reduction of the wave drag effect, which has an important contribution to total drag near the water surface. Reducing the drag experienced by swimmers during the glide off the wall can decrease start and turn times and unnecessary energy loss. Hence, these results suggested that gliding at 0.75 m under the water surface or deeper seemed to be an optimal gliding depth for minimizing drag and improve swimming performance
- The gliding phase in swimming: the effect of water depthPublication . Marinho, D.A.; Barbosa, Tiago M.; Mantripragada, Narendra; Vilas-Boas, João Paulo; Rouard, A.H.; Mantha, Vishveshwar; Rouboa, Abel; Silva, A.J.Aiming to achieve higher performances, swimmers should maximize each component of swimming races. During starts and turns, the gliding phase represents a determinant part of these race components. Thus, the depth position allowing minimizing the hydrodynamic drag force represents an important concern in swimming research. The aim of this study was to analyse the effect of depth on drag during the underwater gliding, using computational fluid dynamics
- The gliding phase in swimming: the effect of water depthPublication . Marinho, D.A.; Barbosa, Tiago M.; Mantripragada, Narendra; Vilas-Boas, João Paulo; Rouard, A.H.; Mantha, Vishveshwar; Rouboa, Abel; Silva, A.J.The aim of this study was to analyse the effect of depth on drag during the underwater gliding. CFD simulations were applied to the flow around a 3D model of a male adult swimmer in a prone gliding position with the arms extended at the front. The domain to perform the simulations was created with 3.0 m depth, 3.0 m width and 11.0 m length. The drag coefficient and the hydrodynamic drag force were computed, using a steady flow velocity of 2.50 m/s for depths of 0.20, 0.50, 1.0, 1.50, 2.01 2.50 and 2.80 m. As the depth increased, the drag coefficient and drag force decreased. The water depth seems to have a positive effect on reducing hydrodynamic drag during the gliding after starts and turns, although a compromise between decreasing drag (by increasing water depth) and gliding travel distance should be a main concern of swimmers.