Kinematic viscosity depends on pressure

[werson tan]

Homework Statement

I was told that kinematic viscosity depends on pressure , but not dynamic viscosity

Homework Equations

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

 

[Chestermiller]

Homework Statement

I was told that kinematic viscosity depends on pressure , but not dynamic viscosity

Homework Equations

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

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.

 

[werson tan]

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.

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

 

[Chestermiller]

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

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