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

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

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INVERTEBRATES AND FLUID DYNAMICS : OFF THE GROUND & MOVIN’ AROUND. FLIGHT. FLIGHT. Airfoil. Thickness . Chord . Angle of attack. FLIGHT. Standard airfoil. Area of relatively low pressure. LIFT. Area of relatively high pressure. FLIGHT. Lift. Resultant force. Drag. - PowerPoint PPT Presentation

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

INVERTEBRATES AND FLUID DYNAMICS:

OFF THE GROUND & MOVIN’ AROUND

Page 2: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

FLIGHT

Page 3: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

FLIGHT

Chord

Thickness

Angle of attack

Airfoil

Page 4: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

FLIGHT

Standard airfoil

Area of relatively low pressure

Area of relatively high pressure

LIFT

Page 5: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

FLIGHT

Lift

Drag

Resultant force

Page 6: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

In flapping flight, need to compromise

1) lift

2) propulsion

3) Lowering of drag

As you increase angle of attack

generated

Page 7: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

H.G. Magnus (1802 – 1870)

Page 8: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

+

LIFT

=

translation circulation

MAGNUS EFFECT

Page 9: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Same principle is used in various sports

Page 10: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Curve ball

Page 11: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Overall flow

-

Translational flow

circulation

=

Page 12: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Circulation around wing

Page 13: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

At the beginning of flight

Establish a counter vortex

Page 14: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Some coefficients of lift

Bird Re – 70002.0

Locust Re – 20001.3

Drosophila Re – 2000.9

Page 15: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering Flight

Page 16: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Encarsia formosa

Wing – 0.6 mm

Mass - .000025 gm

Re - 15

Coefficient of lift (predicted) = 0.02

Coefficient of lift (actual) = 5.0

Page 17: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Clap-and Fling Mechanism

Hovering flight

Page 18: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Flip Mechanism - Dragonfly

Page 19: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering flight

Translational Phase

A) upstroke

B) downstrokeHigh angle of attack

Rotational Phase

A) pronation

B) supinationWhen wing reverses direction

Page 20: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering Flight

Page 21: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering flight

Red arrows – total force and direction

1. Delayed Stall2. Rotational lift 3 Forward motion

Blue arrows – wing position

Page 22: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering flight

Page 23: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Hovering flight

Page 24: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Vortices around a flying animal

Bound vortex Tip vortices

Tip vortices

Page 25: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Tip vortices

Page 26: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Propulsion at very low Re’s

Rowing a boat – propulsive stroke is in lower Re (water) than recovery stroke (air)

Page 27: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

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

Page 28: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

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

Page 29: INVERTEBRATES AND FLUID  DYNAMICS : OFF THE GROUND & MOVIN’ AROUND

Fringed propelling mechanism

Power stroke (fringe expands)

Recovery stroke(fringe collapses)