Magnus effect on a rotating soccer ball at high Reynolds numbers

Kray, Thorsten; Joerg, Franke; Frank, Wolfram

doi:10.1016/j.jweia.2013.10.010

Cited by 33 publications

(26 citation statements)

References 34 publications

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“…The dependence of the lift coefficient on Re (or equivalently flow velocity) for a fixed spin rate was weaker in recent studies as compared to that in older studies. For 6.8 × 10 4 < Re < 15.1 × 10 4 , C L was seen to converge (15) at around 0.5. There has been some agreement that lift has very little or no dependency (22) on Re.…”

Section: Spin Parameter and Reynolds Numbermentioning

confidence: 90%

“…The lift and drag forces were measured via bending stresses in Plexiglas supports. Using hollow sphere halves was found to be favourable because the motor that produces the rotation can be located inside the sphere so that it is not in the airflow (15) . This arrangement resulted in a small blockage ratio and therefore reduced interference.…”

Section: Previous Experimental Methodsmentioning

confidence: 99%

“…It is important to note that the negative Magnus force occurs close to the critical Re, i.e., the point at which the boundary layer becomes turbulent. Regarding the negative Magnus force on a football (15) , the minimum C L was = −0.4 for Re = 43.2 × 10 4 , and a flow with Re = 15.1 × 10 4 displayed a minimum C L of -0.35. No negative force was observed for Re = 6.8 × 10 4 .…”

Section: Negative Magnus Forcementioning

confidence: 96%

“…The average characteristic size from a sample of granite stones was 20-25 mm, matching earlier studies (2) ; hence, this was taken as the focal debris size. Such debris diameters could be characterised by a 100 mm wind tunnel model for Re chosen to be comparable to that in previous literature (11,15) : Re = 5 × 10 4 , 8 × 10 4 and 11 × 10 4 . These values corresponded to tunnel speeds of 7.5, 12.5 and 17.5 m/s, which scaled to takeoff speeds of 30, 50 and 70 m/s, respectively, an appropriate range for most commercial and military aircraft (1) .…”

Section: Reynolds Number Rangementioning

confidence: 99%

“…The error bars showed a reduction in relative error as Re increased, because low wind speeds produced small lift forces that were difficult to measure accurately. MAY 2019 Kray et al 15 : Re = 6.8 ×10 4 Figure 10. Coefficient of lift for a sphere for low Re (stated in the legend) compared with Kray et al (15)…”

Section: Uncertainty Quantificationmentioning

confidence: 99%

See 4 more Smart Citations

Experimental determination of the aerodynamic coefficients of spinning bodies

Nguyen¹,

Corey²,

Chan³

et al. 2019

Aeronaut. j.

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To accurately predict the probabilities of impact damage to aircraft from runway debris, it is important to understand and quantify the aerodynamic forces that contribute to runway debris lofting. These lift and drag forces were therefore measured in experiments with various bodies spun over a range of angular velocities and Reynolds numbers. For a smooth sphere, the Magnus effect was observed for ratios of spin speed to flow speed between 0.3 and 0.4, but a negative Magnus force was observed at high Reynolds numbers as a transitional boundary layer region was approached. Similar relationships between lift and spin rate were found for both cube- and cylinder-shaped test objects, particularly with a ratio of spin speed to flow speed above 0.3, which suggested comparable separation patterns between rapidly spinning cubes and cylinders. A tumbling smooth ellipsoid had aerodynamic characteristics similar to that of a smooth sphere at a high spin rate. Surface roughness in the form of attached sandpaper increased the average lift on the cylinder by 24%, and approximately doubled the lift acting on the ellipsoid in both rolling and tumbling configurations.

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Section: Spin Parameter and Reynolds Numbermentioning

confidence: 90%

Section: Previous Experimental Methodsmentioning

confidence: 99%

Section: Negative Magnus Forcementioning

confidence: 96%