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We know the general cause for turbulence: it is that inertial effects (mass wanting to keep going in the direction that it's going) grow so large that viscous effects cannot contain the system in the laminar flow regime anymore. When those viscous effects cannot slow down a whole chunk of fluid, they are forces acting off-center on a mass: hence they create ...


It has to do with size. For small and slow-moving objects, viscous forces have more weight in comparison to inertial forces. Also, the layer of air close to the surface of an object which moves through air is differently structured. The dimples in a golf ball will make this layer resemble that of larger objects and help to make the flow resemble that around ...


Mythbusters covered this one. They found significant fuel saving at constant speed. Assuming their findings are correct I can only guess that the technique is not used for cosmetic reasons ie few people would want to drive a car that looks like it has been in multiple accidents and covered in dents


Major classes of drag:Two main factors of drag are friction and flow separation. This friction drag is dominant in streamlined shape and pressure drag (drag due to flow separation) is dominant in bluff body. Ways to reduce friction and pressure drag: Turbulent flow has more momentum than laminar flow so they reduces flow separation so pressure drag is ...

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