Can you have fluid dynamics without the fluid?

ie. could you use an abstract mathematical model that allows viscosity and compressability without needing a fluid.
Is there already a model like this?

Keith

You need a fluid of some sort in order to speak of viscosity and compressibility, but fluid could be very broadly defined. Air and mashed potatos are both fluids for instance.

Viscosity and compression are both properties of fluids, so I don't see how you can have them without the fluid to go with it. It's like asking if you could have cause and effect without time.

Hi kaduseus,

Yes, this is perfectly possible. As an analogy, there also exist models that speak of temperature when there is absolutely no heat involved (e.g. neural network models use the word "temperature" to indicate the spontaneous changing of neuron states, it is hence a disturbance to the network). Some models also speak of the "fluid limit" instead of the scaling limit when having a discrete model and turning it into a contineous version (N -> infinity and lattice seperation -> infinity such that the system size remains finite).

This is really just a matter of choosing proper terminology, and often already known words are used to indicate similar properties.

Bye!

Crisp

First a couple of links for people interested in fluid dynamics :-

Virginia Tech (http://www.eng.vt.edu/fluids/msc/gallery/gall.htm) - the f14 film is very nice.

Vortex collisions and more (http://www.eng.nus.edu.sg/mpelimtt/TT_LIM.htm) - watch the movies.

I would have thought you could have a standard model of flow mechanics where the properties such as 'viscosity' are variables that are added to make the model work for any given situation.

This is really just a matter of choosing proper terminology, and often already known words are used to indicate similar properties.

This is the problem that I am having at the moment, what is the inverse of drag called? (slippiness??)

I find that the charged electron in orbit would not emit 'electromagnetic radiation' as this term represents the fluctuation of the electron orbit. It should be named something else.
An atom does not have a 'magnetic field' as such because the term is used to describe a molecular phenomena, I take to using the term 'field potentials'.

Keith