# Fluid equation

1. Aug 25, 2008

### krnhseya

1. The problem statement, all variables and given/known data

Tau = (some constant) * Nu

2. Relevant equations

Shear stress = (some constant) * Kinematic Viscosity

3. The attempt at a solution

n/a

Thanks!

Last edited: Aug 25, 2008
2. Aug 25, 2008

### krnhseya

Is it simply shear rate? ?

3. Aug 25, 2008

### HallsofIvy

I honestly cannot tell what question you are asking!

4. Aug 25, 2008

### krnhseya

Shear stress = (some constant) * Kinematic Viscosity

I am looking for (some constant)'s name.
I remember seeing this equation and I just can't remember this constant's name...(or perhaps what that is called.)

I am thinking the shear rate(?).

5. Aug 25, 2008

### stewartcs

For a Newtonian Fluid, it is the shear rate.

http://en.wikipedia.org/wiki/Newtonian_fluid

CS

6. Aug 25, 2008

### krnhseya

Newtonian Fluid is linear so I guess the shear rate is wrong(?).
If it's non-Newtonian Fluid, is there such constants that goes right in?

7. Aug 26, 2008

### stewartcs

In a Newtonian Fluid the relationship between the shear stress and strain rate is linear. The constant of proportionality is the viscosity. That's why it is linear. The shear rate is used in the equation you where asking about.

In Non-Newtonian Fluids, the viscosity is dependent on the relationship between the shear stress and strain rate which is non-linear.

CS