Air Injection

When will you stop posting off topic stuff? When the entire Forum has noticed you talk much but have nothing to say?

 

I don't see anything about vibration in your link. None of the frequencies mentioned are anywhere close to vibration. They do relate to ground accelerations and inertia however.

-Tom

 

Vibrations, or tremours, are what reduce friction between particulates in mud/earth allowing collapse of whole hillsides. Seismic activity is vibration.

 

I think that is cutting it a bit short.
The dynamic viscosity of air is actually 2 decimals lower than that of water, the kinematic value is obtained after division by density.

It is a good thing that air behaves a bit different from water, otherwise it would require a lot more power to drive with a boat on a trailer.

 

Naah, CDK, no shortcuts here; it is the COMBINATION of the two fluids that gives this result. Much the same way as the speed of sound in a mixture differs from the value of either ingredient!

The method to calculate the kinematic viscosity from a mixture is as follows:

A/ Mean mixture dynamic viscosity acording to Ciccitti: mymix=(x*mygas+(1-x)myliq):
B/ Mean mixture density: 1/rhomix=[x/rhogas+(1-x)/rholiq];
C/ Mixture kinematic viscosity: nymix=mymix/rhomix;

mymix=dynamic viscosity of mixture
mygas=dynamic viscosity of gas component
myliq=dynamic viscosity of liquid component
x=gas mass proportion of mixture
rhomix=mixture density
rhogas=gas density
rholiq=liquid density
nymix=mixture kinematic viscosity

More on this subject to be found in: "A simple friction pressure drop correction for two-phase flow", Mûller-Steinhagen and Heck; Chem. Eng. Process, Vol 20, 1986, pp 297-308

 

I'm not going to argue about it but I did spend five years as a field technician measuring seismicity at ~250 sites in south west BC Canada. The link you offered has nothing to do with vibration. These occilations are what make swimming pool water slosh.

-Tom

 

baeckmo: what is dynamic viscosity?

 

I referred to air only Baeckmo.
By comparing kinetic viscosity only someone might think air is thicker than water.
If I remember correctly there were several opinions about what happens in a gas-liquid mixture. But much more than that I cannot say, and I admit it is a bit meagre. When I studied my financial situation was desperate, yet I had a girlfriend to entertain, so every book I could do without was immediately turned into cash at the used bookshop, something I later regretted.
But I married the girl 47 years ago and she is still with me, so it wasn't all bad.

A thin layer of air can do miracles in some cases, like transporting flour or cement through a thin tube. For boats there seems to be no viable application, yet as you wrote, the subject keeps popping up.
But beware, as the past has proven, it also attracts lunatics like the president/inventor of superior hulls inc, so let us not dwell on the subject too long.

 

Ha ha ha.........................impact !:!:

 

Hehe, good point CDK, guess I'll stop there!!

 

Baeckmo: The speed of sound is dependent on density and elasticity modulus. There is no direct comparison with flow.

 

That's correct, I mentioned it as a further example of "unexpected" nonlinearites due to the mixing of two fluids with differing properties.

 

Here is a better link.
http://www.zetatalk.com/info/tinfo16g.htm

"The most common triggering mechanisms are strong vibrations from earthquakes and excessive amount of water from a winter snow melt of a heavy rainstorm. Earthquakes are the most common type of strong vibrations and thus trigger many mass movements. In many cases, the resulting landslide causes far more damage and poses a greater threat to people than the earthquake itself. "

 

The Naval Research Center says that it works.
http://books.google.com/books?id=HC...resnum=8&ved=0CCYQ6AEwBw#v=onepage&q=&f=false
I also remember reading that it worked in CA Marchaj's book.

 

It a measure of a fluid's resistance to shear stress due to velocity gradients across the main direction of flow.

In the fluid dynamic equations for viscous flow, the dynamic viscosity is always occurring together with the fluid density. This viscosity factor, the kinematic viscosity is dynamic viscosity/fluid density. It is this viscosity factor that influences the balance between viscous forces and mass forces in the flow.