Viscous drag Watch

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ArchimedesSpiral
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#1
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Hi,

I'm having some trouble understanding exactly what viscous drag is. My textbook doesn't go into any detail on it, and I'm having some difficulty getting clarification from the Internet.

Basically, my understanding of drag in a fluid is that it is comprised of two main components: pressure drag and skin friction drag. Pressure drag, as I understand, is caused by the inertia of the fluid that has to be pushed away for the moving object to pass. Skin friction drag, as I understand, is caused by friction (presumably somewhat similar to dry friction, only speed-dependent) between the object and the fluid parallel to the objects direction.

What I don't understand is what viscous drag is. Based on my search so far, I think it is just a synonym of skin friction drag, but I'm not sure. Could someone please tell me if I'm right/wrong and otherwise clarify this for me?

Thanks!
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TheGrandmaster
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A fluid's viscosity is it stickiness or resistance to flow. So viscous drag is a resistive force caused by viscosity. As a body falls through a fluid viscous drag will cause it to accelerate slower. There is an equation for calculating viscous drag on a sphere falling in fluid...



where:
Fd is the frictional force acting on the interface between the fluid and the particle (in N),
mu is the dynamic viscosity (N s/m2,
R is the radius of the spherical object (in m), and
vs is the particle's settling velocity (in m/s).
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Nauman
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Wat is the difference b/w viscous drag and upthrust?? is it same or
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jaroc
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(Original post by Nauman)
Wat is the difference b/w viscous drag and upthrust?? is it same or
Upthrust is the force that acts on a body in a fluid. It comes form the Archimedes law and is a result of pressure's varying with height.

Viscous drag is the result of friction between the body's surface and fluid particles. Unlike upthrust, it depends on velocity of the object.
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Om Dave
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Upthrust is caused by particles pushing the object in the fluid from its side(s) which results in an upward force and viscous drag is when the particles in the fluid interact with the object (causing friction) which slows the object down.
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Stonebridge
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This thread is 3 years old and is now closed.
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