# Does inviscid mean shear stress is negligible?

## Main Question or Discussion Point

I have this flow with Reynold's number in the 10^5, which I think it's big enough to treat the fluid as inviscid, does this also mean I can assume the shear stress is negligible?

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First, what does inviscid mean, by definition?

Second, just because the flow is 10^5 does not mean you can ignore shear stress. What is the object under consideration?

It's a sphere with radius R immersed in water of velocity V. I'm asked to calculate the drag on it. I know the formula for drag is integral of Pcos theta dA + integral of shear stress sin theta dA . And I am not given any information regarding the shear stress, so I thought since the Re is pretty big, we might just treat the shear stress as negligible so only the first term of the equation needs to be calculated.

You could assume inviscid flow but its probably not an accurate assumption. Whats the viscosity or what fluid are you using?

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I have this flow with Reynold's number in the 10^5, which I think it's big enough to treat the fluid as inviscid, does this also mean I can assume the shear stress is negligible?
If u are talking about term "Inviscid"....then u are correct.. its means flow is non viscous ,,,that in return means SHEAR STRESSES are minimum and can be neglected