73 research outputs found
Análise dos Fatos utilizados no 13º Campeonato do Mundo FINA
Para nadar mais rápido, é necessário aumentar a propulsão e diminuir o arrasto. Para o caso,
os fatos de natação de poliuretano podem ter desempenhado um papel importante (Marinho et
al., 2009). Com este estudo pretende-se descrever a distribuição dos diferentes modelos de fatos
de natação usados pelos nadadores durante todas as finais do 13º Campeonato do Mundo de
natação, realizado em Roma e assim perceber as preferências dos nadadores de elevado nÃvel desportivo
13th FINA world Championship: analysis of swimsuits used by elite male swimmers
The polyurethane swimsuits has become the notice
around the pools in the past couple years. A better body position
and the reducing of drag are believed to be some of the reasons that allow
the swimmers wearing these swimsuits to go faster (Kainuma et al.,
2009). The purpose of this study was to verify the distribution of different
swimsuits used by male swimmers during the finals at the last world
championships being held at Rome in 200
Nonuniversal correlations in multiple scattering
We show that intensity of a wave created by a source embedded inside a
three-dimensional disordered medium exhibits a non-universal space-time
correlation which depends explicitly on the short-distance properties of
disorder, source size, and dynamics of disorder in the immediate neighborhood
of the source. This correlation has an infinite spatial range and is
long-ranged in time. We suggest that a technique of "diffuse microscopy" might
be developed employing spatially-selective sensitivity of the considered
correlation to the disorder properties.Comment: 15 pages, 3 postscript figures, accepted to Phys. Rev.
Numerical simulations of a swimmer’s head and cap wearing different types of goggles
The aim of this study was to analyse the effect of swimming goggles on swimming hydrodynamics by numerical simulations. An elite swimmer volunteered for this research. The swimmer's head was scanned both without goggles, and while wearing 3 different types of goggles (Nikko, Ankor and Swedish). Numerical simulations were conducted at 2 m/s with the Fluent code. The condition without goggles showed the highest viscous drag (1.65Â N), followed by the Ankor (1.64Â N), Swedish (1.63Â N) and Nikko (1.62Â N) goggles, respectively. The highest pressure drag was found in the situation without goggles (11.34Â N), followed by the Ankor (10.87Â N), Nikko (10.78Â N) and Swedish (10.20Â N) goggles. The condition without goggles presented the highest total drag (12.99Â N), followed by the Ankor (12.52Â N), Nikko (12.40Â N) and Swedish (11.83Â N) goggles. Thus, Swedish goggles yields the best hydrodynamics, followed by the Nikko and Ankor goggles and lastly without goggles. Thus, goggles minimise the swimmer's drag comparing to not wearing any. The design of the goggles may impose varying drag forces and therefore it is advised to use goggles at least in competition.This work was supported by the Portuguese Foundation for Science and Technology, I.P. [UIDB04045/2020].info:eu-repo/semantics/publishedVersio
The gliding phase in swimming: the effect of water depth
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 dynamic
Three-dimensional CFD analysis of the hand and forearm in swimming
The purpose of this study was to analyze the hydrodynamic characteristics of a realistic model of an elite
swimmer hand/forearm using three-dimensional computational fluid dynamics techniques. A three-dimensional
domain was designed to simulate the fluid flow around a swimmer hand and forearm model in different orientations
(0°, 45°, and 90° for the three axes Ox, Oy and Oz). The hand/forearm model was obtained through
computerized tomography scans. Steady-state analyses were performed using the commercial code Fluent.
The drag coefficient presented higher values than the lift coefficient for all model orientations. The drag coefficient
of the hand/forearm model increased with the angle of attack, with the maximum value of the force
coefficient corresponding to an angle of attack of 90°. The drag coefficient obtained the highest value at an
orientation of the hand plane in which the model was directly perpendicular to the direction of the flow. An
important contribution of the lift coefficient was observed at an angle of attack of 45°, which could have an
important role in the overall propulsive force production of the hand and forearm in swimming phases, when
the angle of attack is near 45°.Lif
Computational fluid dynamics applied to competitive swimming: the role of finger position
The best fingers’ relative position during the underwater
path of the stroke cycle in swimming seems to be an unclear
issue. Even in elite level swimmers, different relative positions of thumb
and finger spreading can be observed. The aim of the current abstract
was to present the hydrodynamic characteristics of a true model of a
swimmer’s hand with different fingers’ positions using computational
CFD
Swimming propulsion forces are enhanced by a small finger spread
The main aim of this study was to investigate the effect of finger spread on the propulsive force production
in swimming using computational fluid dynamics. Computer tomography scans of an Olympic swimmer
hand were conducted. This procedure involved three models of the hand with differing finger spreads: fingers
closed together (no spread), fingers with a small (0.32 cm) spread, and fingers with large (0.64 cm) spread.
Steady-state computational fluid dynamics analyses were performed using the Fluent code. The measured
forces on the hand models were decomposed into drag and lift coefficients. For hand models, angles of attack
of 0°, 15°, 30°, 45°, 60°, 75°, and 90°, with a sweep back angle of 0°, were used for the calculations. The
results showed that the model with a small spread between fingers presented higher values of drag coefficient
than did the models with fingers closed and fingers with a large spread. One can note that the drag coefficient
presented the highest values for an attack angle of 90° in the three hand models. The lift coefficient resembled
a sinusoidal curve across the attack angle. The values for the lift coefficient presented few differences among
the three models, for a given attack angle. These results suggested that fingers slightly spread could allow the
hand to create more propulsive force during swimming
Time limit at the minimum velocity of VO2max and intracyclic variation of the velocity of the centre of mass
The purpose of this study was to analyse the relationship
between time limit at the minimum velocity that elicits maximal
oxygen consumption (TLim-vVO2max) and intra-cyclic variations
of the velocity of the centre of mass (dv) in the four
competitive swimming techniques. Twelve elite male swimmers
SWIMMING BIOENERGETICS
Rev Port Cien Desp 190 6(Supl.2) 185–197
swam their own best technique until exhaustion at their previously
determined v O2max to assess TLim-v O2max. The test
was videotaped in the sagittal plan and the APAS software was
used to evaluate the horizontal velocity of the centre of mass
(Vcm) and its intra-cyclic variation (dv) per swimming technique.
Results pointed out that the strokes that presented
higher intra-cyclic variations also presented larger values of
TLim. Intra-cyclic speed fluctuations (dv) decreased during the
TLim test in the four strokes studied, probably due to fatigue.
Key words: VO2, intra-cyclic velocity variations, time limit, centre
of mass.Authors want to express their gratitude to the Portuguese
National Team, and the Portuguese Swimming Federation, for
their cooperation
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