Recent content by adam7

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    Calculating Viscous and Pressure Drag On A Sphere

    In regards to the adidas jabulani soccer ball that was used at the recent world cup in south africa, it seems that the ball is not any lighter as some may say (it is actually on the heavier side of the strictly regulated limits for ball weight), but just moving faster through the air. I...
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    What Causes the 'Knuckle' Effect in Sports Balls?

    In my view it seems that the ball is not any lighter as some may say (it is actually on the heavier side of the strictly regulated limits for ball weight), but just moving faster through the air. I understand that this is due to all the dimples and ridges on the surface of the ball (tripping a...
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    What Causes the 'Knuckle' Effect in Sports Balls?

    Ok that's great, just what I needed thanks
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    What Causes the 'Knuckle' Effect in Sports Balls?

    Ok ta Zz definate progress here, but I'm still confused as in my original question about why the ball wobbles randomly. Surely if the ball is spinning even if slowly, the boundary layer will only become turbulent on one side of the ball, which would just give regular curve, not erratic wobbles?
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    What Causes the 'Knuckle' Effect in Sports Balls?

    Thanks Zz, that helps explain why the knuckling is more noticable, i.e. this ball knuckles at a speed which most soccer players kick the ball at. But I still don't understand why the ball behaves so randomly? Do the seams on the ball trip turbulence and cause random boundary layer separation? Or...
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    What Causes the 'Knuckle' Effect in Sports Balls?

    The 'Knuckle'(ball) Effect..? I've always been intrigued... how does the 'knuckle' effect (the ball wobbling randomly in the air) - seen in baseball with knuckleballs and oddly enough at the recent soccer world cup with the Jabulani football - work? And why does fewer seams on the ball make...
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    Calculating Viscous and Pressure Drag On A Sphere

    Thanks, I like this idea and it sounds pretty useful as a good comparison showing the affects of the drag on the ball's flight. My issue is that using the formula I stated before I can find the overall drag, its just I was wondering if there was any way I could specifically calculate the...
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    Calculating Viscous and Pressure Drag On A Sphere

    That actually does sound like quite a good idea, unfortunately I don't know either c_v or c_p. If I knew one I'm sure I could derive the other from the overall formula for C, but without knowing the formula for one of these components of the drag force I'm afraid I'm still stuck... :/
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    Calculating Viscous and Pressure Drag On A Sphere

    I've been doing some research on sphere aerodynamics, in particular that of soccer balls, and was wondering if there was any way to separately calculate the pressure / form drag, and also the surface / viscous / skin drag. I know that Stoke's Law of F=6(pi)RnVc, where R is the radius of the...
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