Do Gasses Have Viscosity?

[TriKri]

Fluids have viscosity, but do gasses have it? And in that case, what is the viscosity for normal air (I know air isn't one gas)?

 

[redargon]

yes, a gas is a fluid. here is a nice table of viscosities for air http://www.engineeringtoolbox.com/air-absolute-kinematic-viscosity-d_601.html#

 

[pixel01]

Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.

 

[Archosaur]

Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.

I don't doubt that you are correct, but could you or someone explain this to me?

 

[FredGarvin]

I don't doubt that you are correct, but could you or someone explain this to me?

It is correct. It has to do with momentum transfer between molecules in the gas. Look up Sutherland's formula to see how to calculate a gases viscosity based on temperature.

 

[TriKri]

Like liquid, gas has viscosity of course. But only one thing they are different is for liquid, the higher the temperature, the lower the viscosity and for gas, it's opposite.

I guess that is under a constant pressure, otherwise the viscosity is dependent on the pressure, isn't it?