scholarly journals Dynamics of Spin Bowling: The Normalized Precession of the Spin axis Analysed with a Smart Cricket Ball

2015 ◽  
Vol 112 ◽  
pp. 196-201 ◽  
Author(s):  
Franz Konstantin Fuss ◽  
Batdelger Doljin ◽  
René E.D. Ferdinands ◽  
Aaron Beach
Keyword(s):  
Spin Axis ◽  
Cricket Ball

Models of comets with strongly variable nongravitational effects

1999 ◽  
Vol 173 ◽  
pp. 381-387
Author(s):  
M. Królikowska ◽  
G. Sitarski ◽  
S. Szutowicz
Keyword(s):  
Cometary Nucleus ◽  
Spin Axis ◽  
Reactive Force ◽  
Orbital Elements ◽  
Cometary Nuclei ◽  
Short Period ◽  
Basic Parameters ◽  
Polar Radius ◽  
Cometary Activity ◽  
Nongravitational Effects

AbstractThe nongravitational motion of five “erratic” short-period comets is studied on the basis of published astrometric observations. We present the precession models which successfully link all the observed apparitions of the comets: 21P/Giacobini-Zinner, 31P/Schwassmann-Wachmann 2, 32P/Comas Solá, 37P/Forbes, and 43P/Wolf-Harrington. We used the Sekanina's forced precession model of the rotating cometary nucleus to include the nongravitational terms into equations of the comet's motion. Values of six basic parameters (four connected with the rotating comet nucleus and two describing the precession of spin-axis of the nucleus) have been determined along the orbital elements from positional observations of the comets. The solutions were derived with additional assumptions which introduce instantaneous changes of modulus of reactive force,Aand of maximum of cometary activity with respect to perihelion time. The present precession models impose some contraints on sizes and rotational periods of cometary nuclei. According to our solutions the nucleus of 21P/Giacobini-Zinner with oblateness along the spin-axis of about 0.32 (equatorial to polar radius of 1.46) is the most oblate among five investigated comets.

Development of a Small-spin-axis Controller and Its Application to a Solar Sail Subpayload Satellite

2009 ◽  
Vol 7 ◽  
pp. 25-32 ◽  
Author(s):  
Takanao SAIKI ◽  
Koji NAKAYA ◽  
Takayuki YAMAMOTO ◽  
Yuichi TSUDA ◽  
Osamu MORI ◽  
...  
Keyword(s):  
Solar Sail ◽  
Spin Axis

Spin axis orientation of Ajisai determined from Graz 2kHz SLR data

2010 ◽  
Vol 46 (3) ◽  
pp. 251-256 ◽  
Author(s):  
D. Kucharski ◽  
T. Otsubo ◽  
G. Kirchner ◽  
F. Koidl
Keyword(s):  
Spin Axis ◽  
Axis Orientation

Spin-axis estimation of the Radiation Belt Storm Probes spacecraft using RF Doppler data

2012 ◽  
Vol 73 ◽  
pp. 30-37 ◽  
Author(s):  
Dipak K. Srinivasan ◽  
Gene A. Heyler ◽  
Timothy G. McGee
Keyword(s):  
Radiation Belt ◽  
Spin Axis ◽  
Doppler Data ◽  
Radiation Belt Storm Probes

Spin-axis stabilisation of underactuated rigid spacecraft under sinusoidal disturbance

2008 ◽  
Vol 81 (12) ◽  
pp. 1901-1909 ◽  
Author(s):  
H.-H. Zhang ◽  
F. Wang ◽  
Pavel M. Trivailo
Keyword(s):  
Spin Axis ◽  
Rigid Spacecraft ◽  
Sinusoidal Disturbance

Initial Ball Flight Characteristics of Curve and Instep Kicks in Elite Women’s Football

2012 ◽  
Vol 28 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Alison Alcock ◽  
Wendy Gilleard ◽  
Nick A.T. Brown ◽  
John Baker ◽  
Adam Hunter
Keyword(s):  
Regression Models ◽  
Three Dimensional ◽  
Spin Axis ◽  
Vertical Coordinate ◽  
Ball Flight ◽  
Launch Angle ◽  
Target Center ◽  
Women's Football

Initial ball flight characteristics of curve and instep kicks were investigated. Fifteen international female footballers performed curve and instep kicks from a distance of 20 m from goal and at a 1 m2 target. Seventeen Vicon cameras tracked three-dimensional coordinates of four reflective markers adhered to the ball. Ball flight characteristics were quantified, and the coordinates of the ball relative to the target center were recorded. The lateral launch angle and the angle of the spin axis relative to the horizontal best predicted the horizontal placement of the ball relative to the target. The vertical launch angle, antero-posterior velocity and amount of backspin best predicted the vertical coordinate. Regression models demonstrated how carefully controlled the flight characteristics must be with launch angles constrained within 3° to hit the target. Curve kicks were characterized by significantly greater lateral and vertical launch angles, increased sidespin and spin about the antero-posterior axis, and a more vertical spin axis. This information is beneficial for coaches in training players to achieve the characteristics required to score a goal and avoid a defensive wall. For example, if players consistently kick above or below the target, these findings identify the variables that will help rectify that error.

On the reverse swing of a cricket ball—modelling and measurements

2001 ◽  
Vol 215 (1) ◽  
pp. 45-55 ◽  
Author(s):  
A T Sayers
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Reynolds Numbers ◽  
Flow Conditions ◽  
Drag Forces ◽  
Cricket Ball ◽  
Direct Measurements ◽  
Scale Ratio ◽  
Lift And Drag ◽  
At Will

The phenomenon of reverse swing of the ball in a game of cricket is achieved by very few bowlers, and then only by those who seem able to bowl at speeds in excess of 85 mile/h. It also seems that reverse swing cannot be achieved at will. Rather, it is obtained perhaps by accident as much as by design, its inception being as much of a surprise to the bowler as to the batsman. This would suggest that the flow conditions pertaining to reverse swing are extremely marginal at best. This paper investigates the flow conditions required for reverse swing to occur and presents data describing the lift and drag on the ball. While some direct measurements are made on a cricket ball for comparison purposes, the flow over the ball is modelled through a 2.7:1 scale ratio sphere. This permitted relatively large lift and drag forces to be measured. The results define the range of Reynolds numbers and seam angles over which reverse swing will occur, as well as the corresponding forces on the cricket ball. Flow visualization is used to indicate the state of the boundary layer.

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