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Experimental evaluation of the drag torque, drag force and Magnus force acting on a rotating prolate spheroid
Lukerchenko, Nikolay ; Keita, Ibrahima ; Kvurt, Y. ; Miles, Jiří
The drag torque, drag force and Magnus force acting on a spheroid rotating around its axis of symmetry and moving perpendicularly to this axis in initially quiescent water were studied using experimental data and numerical simulation. The prolate spheroid with ratio of the axes 4/3 was speeded up in special device, which ensured the required rotational and translational velocity in the given plane. A video system was used to record the spheroid motion in water. Using the video records the spheroid translational and angular velocities and trajectory of its center were determined and compared with the results of the numerical simulation. The dependences of the coefficients of the drag torque, drag force and Magnus force on the Reynolds number and dimensionless angular velocity were obtained.
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Experimentální výzkum Magnusovy síly působící na hladkou kouli při vysokých Reynoldsových číslech
Kharlamov, Alexander ; Chára, Zdeněk ; Vlasák, Pavel
Článek popisuje výsledky pokusů s rotující hladkou kulovou částicí při kvazi-stabilním pohybu v klidné vodě. Pohyb částice byl zaznamenán digitální videokamerou a kinematické parametry pohybu částice numericky analyzovány. Bezrozměrný součinitel Magnusovy síly, Reynoldsovo číslo a spin parametr Γ (poměr obvodové rychlosti rotující částice a její translační rychlosti) byly vyhodnoceny z časových řad souřadnic a úhlů rotace částice. Magnusova síla byla určena v závislosti na Reynoldsově čísle a spin parametru pro oblast 3000 < Re < 42000 a 0,1 < Γ <7. Výsledky byly porovnány s literárními údaji a data byly aproximovány jednoduchou funkcí platnou pro oblast 0,5 < Re < 140000 a 0,1 < Γ <10.
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Magnus and Drag Forces Acting on Golf Ball
Kharlamov, Alexander ; Chára, Zdeněk ; Vlasák, Pavel
The paper describes the results of experiments with a rotating golf ball moving quasi-steadily in calm water. The motion of the ball was recorded on a digital video camera. The Cartesian coordinates and the angle of rotation of the ball were determined from the records of motion. The dimensionless drag force coefficient, Magnus force coefficient and translational and rotational Reynolds numbers were calculated from the time series of the ball coordinates and the angle of rotation for each recorded frame. The calculated data were averaged over rectangular cells on experimental domain on the plane of translational and rotational Reynolds numbers, i.e. 1.2 104 < Re < 1.6 104 and 3.8 103 < Reω < 2.7 104. The coefficients were presented in tabulated form.
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