Homework Help: Kinematic viscosity depends on pressure

1. Feb 25, 2016

werson tan

1. The problem statement, all variables and given/known data
I was told that kinematic viscosity depends on pressure , but not dynamic viscosity

2. Relevant equations

3. The attempt at a solution
in my opinion, the dynamic viscosity depends on pressure , since it's formula is μ = tau / (du/dy) , where tau is the stress . and stress can be somehow related to pressure

2. Feb 25, 2016

Staff: Mentor

It is true that pressure is a contributor to the stress tensor, but this contribution is independent of the portion related to the shear viscosity.

3. Feb 25, 2016

werson tan

so , which is correct ? kinematic viscosity or dynamic viscosity depends on pressure?

4. Feb 25, 2016

Staff: Mentor

For an ideal gas, kinematic viscosity varies inversely with pressure (because density is proportional to pressure), and dynamic viscosity does not vary with pressure.