AERODYNAMICS and GOLF ?
04-03-2004, 01:59 PM
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AERODYNAMICS and GOLF ? my ? is....if studies have proven that the dimples in a golf ball allow it to travel further in flight........why doesn't race cars use dimpled hood, fenders, ect.... ? or passenger cars where aerodynamics could be relative to efficiency?
04-03-2004, 09:43 PM
#2
a golf ball is round with inherently poor aerodynamics to begin with. The dimples help improve already poor aerodynamics, not improve already good aerodynamics.
There are two types of aerodynamic drag that an object experiences as it travels through air. The first is drag from laminar flow over the surface of the object. The second is pressure drag, which is the result of a low pressure area developing behind the object as it travels. At high speeds, this low pressure drag can be a significant amount of drag.
Since a sphere is a sphere, there's not much you can do to reduce the drag from air friction. However, the dimples on a golf ball create a turbulent laminar flow along it's surface, and this flow actually follows the contour of the sphere longer, which reduces the amount of pressure drag, thereby allowing the ball to travel further through the air.
Cars and airplanes aren't spheres, so they're able to design far better aerodynamics into their shapes, so in most cases the significant portion of drag is from air friction, not pressure drag.
There are two types of aerodynamic drag that an object experiences as it travels through air. The first is drag from laminar flow over the surface of the object. The second is pressure drag, which is the result of a low pressure area developing behind the object as it travels. At high speeds, this low pressure drag can be a significant amount of drag.
Since a sphere is a sphere, there's not much you can do to reduce the drag from air friction. However, the dimples on a golf ball create a turbulent laminar flow along it's surface, and this flow actually follows the contour of the sphere longer, which reduces the amount of pressure drag, thereby allowing the ball to travel further through the air.
Cars and airplanes aren't spheres, so they're able to design far better aerodynamics into their shapes, so in most cases the significant portion of drag is from air friction, not pressure drag.
04-06-2004, 02:45 PM
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Originally Posted by jRaskell
turbulent laminar flow
Good explanation. I learned something.
Tony
(I only got a "B" in Fluid Dynamics)
04-07-2004, 04:08 PM
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Good explanation for a short one. The key concept is flow separation. Flow separation in almost any case means large drag increase. The dimples in the surface of the golf ball delay the flow separation. The dimples are turbulators and actually create turbulent flow in the boundary layer. Sure turbulent flow creates more drag than laminar flow, but turbulent flow has better adhesion and tends to resist separation. The contribution to drag that separation introduces is far greater than that of boundary turbulence. The drag reduction is thus accomplished by separation delay.