Physics of Hydraulics :: physics hydraulics

Missing Figures/Equations History The type of physics that I will be presenting is a branch of Fluid Mechanics. Fluid mechanics studies the physics of gases and liquids. Hydraulics is defined as: "a branch of science that deals with practical applications of liquid in motion." Merriam-Webster's Medical Dictionary, via www.dictionary.com The science started over thousands of years ago with Aristotle (384-322 B.C.) and Archimedes (287-212 B.C.). Many European scientists also contributed to hydraulics, including da Vinci, Mariotte and Boyle. The scientist who discovered the main principle I will be talking about is Pascal. A French scientist who studied math and physics. His work included studying atmospheric pressure, conic sections and the principles of hydrostatics. After Pascal there is Bernoilli, Franklin and Froud, who all also contributed to the science of hydraulics. How it works (the physics part) The basic rule of using hydraulic power is Pascal's Principle. Pascal's Principle: pressure exerted on a fluid is distributed equally throughout the fluid. Hydraulics uses incompresible liquids so the applied pressure from one end (small arrow) is equal to the desired pressure on the other end (big arrow). The big arrow is pointing toward a piston that is free to move, and is sometimes connected to a rod. When the force is applied, the piston moves up or down. The equations are: equations Of course, as Prof. Newman says, "there is no free lunch," In order to move the larger area, the smaller area has to move a lot in order to move the larger area a little. The larger area is nine times greater than the smaller area. In order to move the larger piston one inch, the smaller piston has to move nine inches. The Uses of Hydraulics Hydraulics are used in many ways. Most of them are used everyday and not even thought about. Here are some examples of how hydraulics are used. They are all machines (I'm a mechanical engineer!) Car Brakes Car brakes work when you push the brake pedal, it pushes the small piston. The piston applies pressure on the brake fluid, which press the brake pads on the large pistons. The brake pads come into contact with the brake drum and slows the car down, eventually stopping the car. Airplanes Airplanes and jet planes use hydraulics in many places. * Adjusting wings * Putting out/bringing in landing gear * opening/closing doors Real Life Hydraulics Unfortunately applying hydraulics in real life isn't so simple. There are a few things to consider if you are planning on designing and building hydraulic equipment.