Simulation of Aerodynamics of the Cricket Ball with Soil Conditions of the Pitch
This paper describes Simulation of Aerodynamics of the Cricket Ball using digitalanlyzer version1.2 .The results show the deviation of ball depend on aerodynamics properties. This paper also shows that different types of ball have different observed co efficient with different types of surface. This paper will help for referring decision to third umpire in LBW.
Aerodynamics of a cricket ball
Abstract This paper describes experiments performed on stationary and rotating cricket balls to determine the aerodynamic forces acting on the ball over a range of bowling speeds and seam angles. Lift, drag and side forces were measured directly and it was found they exhibited magnitudes in the order of 1.4, 1 and 0.4 N, respectively, for the stationary ball. At air velocities above 20 m/s, the lift force increased with increasing air speed being weakly influenced by the vertical seam angle. At 10 m/s air speed, the side force began to increase steadily with air speed for seam angles up to 70°. At 80° the side force direction reversed due to the sudden movement of the separation point on the surface of the ball. Roughening one side of the ball increased the side force but delayed its reversal at 80° seam angle until a marginally higher velocity was reached. When top spin was applied to the smooth ball, the lift force increased almost linearly in the negative direction but there was no resultant side force. When a roughened ball was spun, the negative lift force was constant at all air speeds over a range of rotational speeds. The development of the measured forces are discussed in terms of boundary layer flow and Magnus effect.
Pressure Fluctuations in a Separated Flow Region
This paper describes a preliminary experimental investigation of pressure fluctuations in a separated flow behind a thin fence. Methods of determining the position of recombination point, which is closely related to the position of maximum sound‐pressure level, are discussed. Noise sources within the flow are identified. Significant and parasitic variables are noted and a dimensional analysis is presented. A similarity relation is also presented, relating sound levels to frequencies and free‐stream velocities. Graphs of the variation of power spectral density with frequency, and sound level with distance behind the fence are given for distances up to 50 fence heights behind the fence. It has been found that the frequency spectra alter considerably with distance behind the fence and that the maximum sound level behind a fence is about eight times that in a turbulent boundary layer, with the same free‐stream dynamic head.