Why should fluid flows strictly adhere to the continuum prin

Why should fluid flows strictly adhere to the continuum principle?

Solution

let us consider a gas in a container (e.g. bottle with air, or LPG cylinder). the gas is made up of a large number of individual molecules all moving about. now, there are bound to be collisions; which are of two types:

if we measure the distance traveled by each molecule in the container BEFORE it experiences a collision and take an average of these distances for all the molecules, we obtain a distance called \'Mean Free Path\'.

now if you want to study the properties of the gas in the container, if the length scale of the container is MUCH LARGER than the mean free path of the molecules, the CONTINUUM APPROXIMATION holds good; that is: the gas and container can be treated as one big continuous body and the effect of the various transport phenomena can be studied- this is why temperature, pressure and various other properties are called MACROSCOPIC.
e.g.: temperature: there is nothing called temperature of a molecule. we study the temperature of the gas--> temperature is felt as the net kinetic energy of the collisions in the container! the more energetic the molecules are, the more they collide and the HOTTER is the gas!

highlighting the 2nd point fluid when flown it collide with walls and each othe so concept of continuum is strictly adhere to continuum principle