PHYS16 – Lecture 31 Fluids: Bernoulli’s Principle November 12, 2010 What is Google really trying to say?

No Seriously!!

Outline for Fluids Pressure and Pascal’s Principle Buoyant Force and Archimedes’ Principle Fluid dynamics – Ideal Fluids – Equation of Continuity – Bernoulli’s Equation

Bernoulli’s Equation For an ideal fluid flowing in a pipe, pressure in the pipe is related to the velocity and height of fluid

Example: Blood Pressure What would happen if the doctor took a blood pressure reading at the wrist instead of on the bicep? A)Blood pressure would be higher B)Blood pressure would be lower C)Blood pressure would be the same

Example: Aneurysm In an aneurysm the arterial wall weakens and the diameter increases. Why does this increase the chance of rupture? A increases, v decreases, P increases

Example: Draining Water What happens when you drain a bottle of water? As water height decreases, speed at bottom decreases

Example: Water jets out of a bottle Which jet will have the largest range?

What is wrong with this cartoon? On a windy day in 1735, a new wig gives Bernoulli an idea. Wind is blowing in the wrong direction…

What happens if fluid is not ideal?

Poiseuille's Law When frictional forces dominate velocity decreases – Viscous fluids – Small Diameters Ideal – larger diameters With Friction – small diameters

Main Points Buoyant force Ideal fluid is incompressible, laminar, nonviscous, and irrotational Equation of continuity Bernoulli’s Equation

What’s left… 2 online and 2 written homeworks 1 lab homework 1 formal lab report 1 lab 1 last cumulative exam