Tuesday, July 5, 2011

Fluid Mechanics

Bernoulli's Principle

Bernoulli's equation employing the work-energy theorem and energy conservation.

The total energy in a steadily flowing fluid system is a CONSTANT along the flow path/throughout the displacement. (Fluid pressure is inversely proportional to its velocity.)

The total energy of the system is equal to the sum of the PE + KE + and Pressure Energy.


Bernoulli's Principle, when the heights are equal (y1 = y2, cancel):
- Fast flowing fluids have LOW pressure
- Slow flowing fluids have HIGH pressure

Continuity Equation: Q = A1v1 = A2v2

(Area & velocity are INVERSELY PROPORTIONAL!!!)
- If the tube narrows; speed will INCREASE
- If the tube widens, speed will DECREASE


"10 kits blown and scattered about" hahaha
- Water always flows from high to low pressure

Density of Water (expressions):
Pressure = Pa (pascals!!!)
- 1 Pa = 1 N/m2
- atmospheric pressure = 100,000 Pa
- trick: 10m of water depth adds about 1 atm of pressure
- pressure is produced by the collisions of fluid molecules with the surfaces with which the fluid is in contact
Poiseuille's Principle
An equation which describes laminar flow in a straight tube. V=P¹r4/8nl, where V= flow P= driving pressure r= radius of tube n= fluid viscosity l= length of tube.
"Thus, when one describes a patient as having "high blood pressure", it means that their heart is generating a very large P1 in order to produce the necessary Q to get blood to the tissue in a timely fashion."
http://www.youtube.com/watch?v=-jyBY726np4&feature=results_video&playnext=1&list=PL05679B8070040C79

The Hydraulic Press
http://www.youtube.com/watch?v=TjzKpke0nSU


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