Fluid Mechanics   Fluids   The particles flow and fit their container Liquids and gases Ice? Glaciers!   Temperature and pressure determine the state of matter 9/28/2016APHY1011

Fluid Mechanics   Density   Mass per unit volume This assumes the object has a uniform density   Gases can be compressed/expanded easily so their densities vary greatly. Liquids and solids are nearly incompressible 9/28/2016APHY1012

Fluid Mechanics   Pressure   Force per unit area Unit: N/m 2 or Pa   P air (at sea level) ~ 100,000 Pa ~ 1 bar ~ 15 psi Weather, tires, shoes, needles, knives, water saws 9/28/2016APHY1013

Fluid Mechanics   Pressure in Fluids   Pressure changes with depth in a fluid   Pressures can be added P total = P water + P air   Differences in pressure Storms, airplanes, submarines 9/28/2016APHY1014

Fluid Mechanics   Measuring Pressure   Barometers: mercury vs. water Measure atmospheric pressure 9/28/2016APHY1015

Fluid Mechanics   Manometers Measure pressure of an enclosed gas Sphygmomanometer (blood pressure) 9/28/2016APHY1016

Fluid Mechanics   Archimedes’ Principle   An object in a fluid experiences an upward force equal to the weight of the displaced fluid. Applications: submarines, fish, boats, balloons 9/28/2016APHY1017

Fluid Mechanics   Bernoulli’s Principle   The volume of fluid passing any point at a given time is constant. Therefore, fluids move faster through narrow openings. 9/28/2016APHY1018

Fluid Mechanics   Bernoulli’s Principle   If the speed of a fluid is high then its internal pressure is low   Laminar vs. Turbulent flow Laminar vs. Turbulent flow9/28/2016APHY1019

Fluid Mechanics   Bernoulli’s Principle 9/28/2016APHY10110