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Fluid Mechanics. Ch-8 Buoyancy Pressure Flow. Fluids. Fluids flow and alter shape Which states of matter are fluid? Liquid Gas Plasma. Gasses fill and conform to their container. Chlorine gas Cl 2. Plasma ’ s conform to magnetic fields.
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Fluid Mechanics Ch-8 Buoyancy Pressure Flow
Fluids • Fluids flow and alter shape • Which states of matter are fluid? • Liquid • Gas • Plasma
Gasses fill and conform to their container • Chlorine gas Cl2
Plasma’s conform to magnetic fields • At PPPL they are experimenting on the fusion of hydrogen plasma
Density • = m/V • “rho” = mass/volume • Density of Steam = 0.598 kg/m3 • Density of Mercury = 13.6 x 103 kg/m3
Buoyancy • FB = Fg (of displaced fluid) • = mog
Archimedes Principle • Fnet = mfg - mog
Fluid Pressure • P = F/A • Force/unit area • Pounds/in2 (Psi) • Or N/m2 (Pascals) 4000 N/m2
Fluid Pressure • P = F/A • Force/unit area • PSI (lbs/insquared)
Pressure increases as area applied decreases • F1/A1 = F2/A2
Syringe hydraulic lift • I raise a 10 N rock with a hydraulic piston that is 13 mm in radius using water connected to a 1.5 mm radius syringe. How much force is necessary for this lift to raise the rock?
Pressure as a Function of Depth • P = Po + rgh
Submarine Ballast Tanks • The density of the whole device is adjusted by releasing compressed air
Buoyant force results from differing pressure at depth FB=A(Po+rgh2)-A(Po+rgh1) FB=rg(h2-h1)A FB=rgV FB=mfg That’s Archimedes Principle
The Coanda Effect • Fluid adheres to surfaces • Flowing fluids are directed by curved surfaces
Bernouli’s Principle on Air foils • Air flowing across and air foil flows faster across the top • Pressure is lower of the air flows faster • Fnet is upward
Coanda Effect breaks down at high angles of attack • The Coanda effect guides the air flow along the surface • The air flow breaks free and turbulent flow results • Stall occurs
Coanda Develops First Jet engine aircraft, 1910 It crashes, he loses funding Lost technology for 30 years