# Conceptual questions in Fluid Mechanics

1. Oct 15, 2008

### stunner5000pt

1. The problem statement, all variables and given/known data
Define:Static pressure
Dynamic Pressure
Continuum hypothesis
Kinetic Viscosity
Kinematic Viscosity

2. The attempt at a solution

The real question is : are these answers sufficient?

Static Pressure
- The pressure exerted by a fluid on an object placed within the fluid is called the static pressure.

Dynamic Pressure - The pressure exerted by a fluid on an object that is moving through the fluid. This is given by:
$$q = \frac{1}{2} \rho v^2$$

I get the feeling that this is wrong...

Continuum hypothesis - the region to be described can be subdivided into a set of (infinitesimal) volume elements, each of which simultaneously:
1) is small enough to be considered uniform (i.e. any spatial variations in properties -- such as r, v,T, p -- inside the volume element are negligible); and
2) is large enough to contain a statistically large number of molecules.

Kinetic Viscosity - I think he means dynamic viscosity
The definition for dynamic viscosity is the force per unit area a liquid exerts on two parallel plates that enclose the liquid. I would be more concise with this explanation when i'm writing it out that is, i will give an example.

Kinematic Viscosity - The ratio of the dynamic viscosity and the density of the fluid.

I am not sure about the last two definitions, i think they are too short. However i have looked through a few textbooks - Lifsitz/Landau, Houghton/Carpenter (my course text), Batchelor, but none of them have yielded a satisfactory answer for the last two definitions.
I would really appreciate your help!

Thank you