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

2. FLIGHT

3. Chord Thickness Angle of attack Airfoil

4. FLIGHT Standard airfoil Area of relatively low pressure Area of relatively high pressure LIFT

5. FLIGHT Lift Drag Resultant force

6. In flapping flight, need to compromise 1) lift 2) propulsion 3) Lowering of drag As you increase angle of attack generated

7. H.G. Magnus (1802 – 1870)

8. + LIFT = translationcirculation MAGNUS EFFECT

9. Same principle is used in various sports

10. Curve ball

11. Overall flow - Translational flow circulation =

12. Circulation around wing

13. At the beginning of flight Establish a counter vortex

14. Some coefficients of lift BirdRe – 70002.0 LocustRe – 20001.3 Drosophila Re – 2000.9

15. Hovering Flight

16. Encarsia formosa Wing – 0.6 mm Mass -.000025 gm Re - 15 Coefficient of lift (predicted) = 0.02 Coefficient of lift (actual) = 5.0

17. Clap-and Fling Mechanism Hovering flight

18. Flip Mechanism - Dragonfly

19. Hovering flight Translational Phase A) upstroke B) downstroke High angle of attack Rotational Phase A) pronation B) supination When wing reverses direction

20. Hovering Flight

21. Hovering flight Red arrows – total force and direction 1. Delayed Stall2. Rotational lift3 Forward motion Blue arrows – wing position

22. Hovering flight

24. Vortices around a flying animal Bound vortexTip vortices

26. Propulsion at very low Re’s Rowing a boat – propulsive stroke is in lower Re (water) than recovery stroke (air)

27. Propulsion at very low Re’s What about smaller animals that have to do both in low Re? Cladoceran Dytiscid beetle Thrips Nepticulid moth Mymarid wasp Ptiliid beetle Aquatic Aerial

28. Propulsion at very low Re’s What about smaller animals that have to do both in low Re? Relative sizes Size difference and different viscosity of medium  similar low Re’s

29. Fringed propelling mechanism Power stroke (fringe expands) Recovery stroke (fringe collapses)