Drag force on a sphere moving through a fluid

AI Thread Summary
The drag force experienced by a sphere moving through a fluid is influenced by turbulence, with the force expressed as F = kp(R^2)(v^2), where k is a constant, p is the fluid density, R is the sphere's radius, and v is its speed. This relationship indicates that the drag force is proportional to the square of the velocity and the square of the radius of the sphere. For accurate calculations in real-world scenarios, the complexity often necessitates the use of simulations rather than straightforward analytical methods. Understanding drag force is crucial for various applications in fluid dynamics. The discussion highlights the challenges of calculating drag forces in practical situations.
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A body moves through a fluid, a retarding force due to turbulence may be experienced. In case of a sphere of radius R moving with speed v through a stationary fluid of density p which it at rest, this force is given by
F = kp (R^2) (v^2)
k is a constant.
Why F is proportional to kp (R^2) (v^2) ?
 
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Google for "drag force calculation" and you'll find many good derivations. In practice, with real objects moving through real fluids, the calculations are hairy enough that we often resort to simulations.
 

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