Numerical investigation of Magnus effect on dimpled spheres

Beratlis, Nikolaos; Squires, Kyle D.; Balaras, Elias

doi:10.1080/14685248.2012.676182

Cited by 13 publications

(15 citation statements)

References 9 publications

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“…For the golf ball, the lift force is slightly smaller at the supercritical Reynolds number when compared to the subcritical Reynolds number, whereas for the smooth sphere, the supercritical lift force is approximately twice as large as the subcritical lift force, as also evidenced in Table 1 . On the other hand, in the golf ball case, Beratlis et al [ 7 ] mentioned in their numerical results that “the maximum lift obtained in the beginning of the supercritical regime is higher than that in the subcritical regime”, and the trend is reversed to our results. The possible explanation of this qualitative disagreement comes from the difference of critical Reynolds number between these two cases (around 8 × 10 4 in our case and 5 × 10 4 in [ 7 ]).…”

Section: Resultscontrasting

confidence: 90%

“…Beratlis et al [ 7 ] extended the work of Smith et al [ 3 ] to the investigation of flow past rotating golf balls. They conducted the direct numerical simulations of the rotating golf ball with the same spin parameter at four different Reynolds numbers spanning from the subcritical regime to the supercritical regime.…”

Section: Introductionmentioning

confidence: 99%

“…This conclusion is analogous to the assumption by Bearman and Harvey [ 1 ]. However, although the negative Magnus effect was demonstrated by statistics, no details concerning the development of unsteady forces exerted on the spinning golf ball was provided in the work of Beratlis et al [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of the Flow Past a Rotating Golf Ball and Its Comparison with a Rotating Smooth Sphere

Tsubokura

Tsunoda

2017

Flow Turbulence Combust

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Large-eddy simulations are conducted for a rotating golf ball and a rotating smooth sphere at a constant rotational speed at the subcritical, critical and supercritical Reynolds numbers. A negative lift force is generated in the critical regime for both models, whereas positive lift forces are generated in the subcritical and supercritical regimes. Detailed analysis on the flow separations on different sides of the models reveals the mechanism of the negative Magnus effect. Further investigation of the unsteady aerodynamics reveals the effect of rotating motion on the development of lateral forces and wake flow structures. It is found that the rotating motion helps to stabilize the resultant lateral forces for both models especially in the supercritical regime.

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Section: Resultscontrasting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of the Flow Past a Rotating Golf Ball and Its Comparison with a Rotating Smooth Sphere

Tsubokura

Tsunoda

2017

Flow Turbulence Combust

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“…Particular attention will be focused towards how the dimples affect the generation of lift force under self-rotating conditions. The mechanism of the inverse Magnus effect on the golf ball [1,25] and its comparison with the smooth sphere will be investigated in detail.…”

Section: Discussionmentioning

confidence: 99%

Numerical Investigation of the Flow Around a Golf Ball at Around the Critical Reynolds Number and its Comparison with a Smooth Sphere

Tsubokura

Tsunoda

2015

Flow Turbulence Combust

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The flow over a stationary golf ball has been numerically investigated by conducting large-eddy simulations in the subcritical, critical and supercritical regimes. A direct comparison of features of flow fields was made to a smooth sphere model. Particular attention was paid to the effect that the golf ball dimples have on the development of lateral force and wake structures. In the subcritical regime, the lateral force varies irregularly in time for both the golf ball and the smooth sphere, and the wake structures of these two models appear to be similar, indicating the limited effect of the surface roughness on the flow behaviors in this regime. In the critical regime, both the golf ball and the smooth sphere exhibit a larger magnitude lateral force oscillation compared to the subcritical cases, while the wavelengths of the flow structures show differences between the golf ball and the smooth sphere. In the Makoto Tsubokura Flow Turbulence Combust supercritical regime, both the golf ball and the smooth sphere are subjected to a nonzero lateral force during a long time interval. However, the magnitude of the lateral force acting on the golf ball is much smaller due to the relatively more concentrated and less asymmetric wake structures compared to the smooth sphere.

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“…The use of a staggered grid was also helpful in decreasing the number of singularities, since the azimuthal and axial velocity components, as well as pressure, are not defined at r = 0 for such grid. More details about axis treatment are discussed by Akselvoll & Moin (1996) and Verzicco & Orlandi (1996), while applications of our cylindrical coordinate solver can be found in Smith et al (2010), Posa et al (2011), Beratlis, Squires & Balaras (2012), , Balaras, Schroeder & Posa (2015) and Posa, Lippolis & Balaras (2015). All spatial derivatives are approximated with second-order central differences.…”

Section: Methodologies and Computational Set-upmentioning

confidence: 99%

A numerical investigation of the wake of an axisymmetric body with appendages

Posa

Balaras

2016

J. Fluid Mech.

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We report wall-resolved large-eddy simulations of an axisymmetric body of revolution with appendages. The geometry is that of the DARPA SUBOFF body at 0 yaw angle and a Reynolds number equal to Re L = 1.2 × 10 6 (based on the free-stream velocity and the length of the body). The computational grid, composed of approximately 3 billion nodes, is designed to capture all essential flow features, including the turbulent boundary layers on the surface of the body. Our results are in good agreement with measurements available in the literature. It is shown that the wake of the body is affected mainly by the shear layer from the trailing edge of the fins and the turbulent boundary layer growing along the stern, while the influence of the wake of the sail is minimal. In agreement with the reference experiments, a bimodal behaviour for the turbulent stresses is observed in the wake. This is due to the displacement of the maximum of turbulent kinetic energy away from the wall along the surface of the stern, where the boundary layer is subjected to strong adverse pressure gradients. The junction flows, produced by the interaction of the boundary layer with the leading edge of the fins, enhance this bimodal pattern, feeding additional turbulence in the boundary layer and the downstream wake. The evolution of the wake towards selfsimilarity is also investigated up to nine diameters downstream of the tail. We found the mean flow approaches this condition, while its development is delayed by the wake of the appendages, especially by the flow coming from the tip of the fins. However, the width of the wake and its maximum momentum deficit follow the expected powerlaw behaviour on the side away from the sail. The second-order statistics, on the other hand, are still far from self-similarity, which is consistent with experimental observations in the literature.

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Numerical investigation of Magnus effect on dimpled spheres

Cited by 13 publications

References 9 publications

Numerical Investigation of the Flow Past a Rotating Golf Ball and Its Comparison with a Rotating Smooth Sphere

Numerical Investigation of the Flow Past a Rotating Golf Ball and Its Comparison with a Rotating Smooth Sphere

Numerical Investigation of the Flow Around a Golf Ball at Around the Critical Reynolds Number and its Comparison with a Smooth Sphere

A numerical investigation of the wake of an axisymmetric body with appendages

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