Does inviscid mean shear stress is negligible?

In summary, the flow with a Reynolds number of 10^5 can be considered inviscid, meaning that the shear stress can be assumed to be negligible. However, this assumption may not be accurate and depends on the viscosity of the fluid being used. The object under consideration is a sphere immersed in water with a velocity of V, and the task is to calculate the drag on it using the formula for drag. The formula includes terms for both pressure and shear stress, but since no information is given about the shear stress, it was assumed to be negligible due to the high Reynolds number.
  • #1
corona7w
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0
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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  • #2
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?
 
  • #3
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.
 
  • #4
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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  • #5
corona7w said:
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
 

1. What does it mean for a flow to be inviscid?

Inviscid flow is a type of fluid flow in which the effects of viscosity, or internal friction, are considered to be negligible. This means that the fluid is assumed to have zero viscosity and therefore no shear stress, resulting in a flow that is smooth and does not experience any resistance or energy loss.

2. How is inviscid flow different from viscous flow?

Viscous flow is a type of fluid flow in which the effects of viscosity are significant and cannot be neglected. In contrast, inviscid flow assumes zero viscosity and therefore no shear stress, resulting in a flow that is free from friction and energy loss.

3. Does inviscid flow exist in real-life scenarios?

Inviscid flow is an idealized concept and does not exist in real-life scenarios. However, it is a useful simplification in certain situations where the effects of viscosity are small and can be neglected, such as in low-speed flows of gases or liquids with low viscosity.

4. How does the assumption of inviscid flow affect the equations used to describe fluid flow?

The Navier-Stokes equations, which are used to describe fluid flow, include terms for viscosity and shear stress. In inviscid flow, these terms are assumed to be zero, resulting in simplified equations known as the Euler equations. These equations are valid for inviscid flow but do not account for the effects of viscosity.

5. What are some common applications of inviscid flow analysis?

Inviscid flow analysis is commonly used in aerodynamics, such as in the design of airplanes and rockets. It is also used in the study of water waves, such as ocean waves and tsunamis. In addition, inviscid flow analysis is used in the development of computational fluid dynamics (CFD) codes, which are used to simulate fluid flow in various engineering applications.

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