INVERTEBRATES AND FLUID DYNAMICS: OFF THE GROUND & MOVIN’ AROUND.

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    17-Jan-2016

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PowerPoint PresentationINVERTEBRATES AND FLUID DYNAMICS:OFF THE GROUND & MOVIN AROUNDFLIGHTFLIGHTChord Thickness Angle of attackAirfoilFLIGHTStandard airfoilArea of relatively low pressureArea of relatively high pressureLIFTBUT THIS IS ONLY FOR AIRCRAFT4FLIGHTLiftDragResultant forceIn flapping flight, need to compromise1) lift2) propulsion3) Lowering of dragAs you increase angle of attackgeneratedH.G. Magnus (1802 1870)+LIFT=translationcirculationMAGNUS EFFECTSame principle is used in various sports Curve ballOverall flow-Translational flowcirculation=Circulation around wingAt the beginning of flightEstablish a counter vortexSome coefficients of liftBirdRe 70002.0LocustRe 20001.3Drosophila Re 2000.9Hovering Flight Encarsia formosaWing 0.6 mmMass - .000025 gmRe - 15Coefficient of lift (predicted) = 0.02Coefficient of lift (actual) = 5.0Clap-and Fling MechanismHovering flightFlip Mechanism - DragonflyHovering flightTranslational PhaseA) upstrokeB) downstrokeHigh angle of attackRotational PhaseA) pronationB) supinationWhen wing reverses directionHovering FlightHovering flightRed arrows total force and direction 1. Delayed Stall2. Rotational lift 3 Forward motionBlue arrows wing positionHovering flightHovering flightVortices around a flying animalBound vortexTip vorticesTip vorticesTip vorticesPropulsion at very low ResRowing a boat propulsive stroke is in lower Re (water) than recovery stroke (air)Propulsion at very low ResWhat about smaller animals that have to do both in low Re?CladoceranDytiscid beetleThrips Nepticulid mothMymarid waspPtiliid beetleAquatic AerialPropulsion at very low ResWhat about smaller animals that have to do both in low Re?Relative sizesSize difference and different viscosity of medium similar low Res Fringed propelling mechanismPower stroke (fringe expands)Recovery stroke(fringe collapses)

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