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AERODYNAMICS AND WINDTUNNELS

AERODYNAMICS AND WINDTUNNELS. DEFINITION. AERODYNAMICS: IS THE STUDY OF THE FORCES EXERTED BY AIR OR OTHER GASES IN MOTION. DESIGN APPLICATIONS. WHY SHOULD WE CARE ABOUT AERODYNAMICS?

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AERODYNAMICS AND WINDTUNNELS

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  1. AERODYNAMICS AND WINDTUNNELS

  2. DEFINITION AERODYNAMICS: IS THE STUDY OF THE FORCES EXERTED BY AIR OR OTHER GASES IN MOTION

  3. DESIGN APPLICATIONS WHY SHOULD WE CARE ABOUT AERODYNAMICS? BECAUSE IT SIGNIFICANTLY AFFECTS THE PERFORMANCE & SAFETY OF MANY OF THE THINGS WE USE AND THINGS WE DO: AIRCRAFT SPACECRAFT AUTOMOBILES AND TRUCKS ENGINES (Gas turbines, reciprocating engines, etc.) AIR HANDLING SYSTEMS (fans, blowers, air conditioners, etc.) BUILDINGS WIND TURBINES SPORTS (Ski jumping, speed skating, bicycle racing, windsurfing, yacht racing, etc.)

  4. AERO DESIGN PROCESS THE SCIENTIFIC METHOD: FOR THEORY TO BECOME LAW IT MUST BE TESTABLE (otherwise it’s philosophy) THE WIND TUNNEL IS THE PRIMARY TEST VEHICLE FOR AERODYNAMIC DESIGN

  5. GOVERNING LAWS OF PHYSICS UNDERSTANDING AERODYNAMICS CONSERVATION OF ENERGY NEWTON’S THIRD LAW OF MOTION POTENTIAL & KINETIC ENERGY CONTINUITY EQUATION

  6. ENERGY THE LAW OF CONSERVATION OF ENERGY energy can neither be created nor destroyed, but only changed from one form into another or transferred from one object to another the total amount of energy in a closed system remains constant

  7. LAWS OF MOTION NEWTONS THIRD LAW FOR EVERY ACTION THERE IS AN (OPPOSED) EQUAL AND OPPOSITE REACTION

  8. ENERGY TRANSFORMATION POTENTIAL ENERGY PE = mass x g x height = weight x height KINETIC ENERGY KE = ½ mass x velocity2 = weight x velocity2 2g

  9. DEFINITION THE FORCES EXERTED BY AIR ARE MANIFEST IN PRESSURE

  10. CONTINUITY EQUATION FLOW THROUGH A CONSTRAINED REGION Continuity Equation W1 = W2 = Wn flow = density x area x velocity W = d x A x V n 2 1

  11. THE CONCEPT OF PRESSURE STATIC PRESSURE OBSERVER MOVING WITH THE AIR V = 0

  12. THE CONCEPT OF PRESSURE DYNAMIC (TOTAL) PRESSURE Pressure due to velocity of air relative to the velocity of the object OBSERVER MOVING WITH THE OBJECT

  13. THE CONCEPT OF PRESSURE RELATIONSHIP BETWEEN STATIC AND TOTAL PRESSURE Total Temp ≈ Static Temp x (1 + c x V2) Total Press ≈ Static Press x (1 + c x V2)3.5 Total Press ≈ Static Press x (Total/Static Temp)3.5

  14. DEFINITION AERODYNAMICS OF WINGS

  15. VELOCITY IN A CONSTRAINED SPACE VELOCITY IS GOVERNED BY THE CONTINUITY EQUATION Density (d) varies with T & P T & P remain constant unless heat and/or work is added or removed (conservation of energy), thus d = constant Therefore: W = constant = d x A x V = constant x A x V Thus V varies only with A (V = constant/A)

  16. AERODYNAMICS OF WINGS FLOW OVER A WING

  17. AERODYNAMICS OF WINGS PRESSURE DISTRIBUTION AROUND A WING

  18. AERODYNAMICS OF WINGS C

  19. AERODYNAMICS OF WINGS ANGLE OF ATTACK As the angle of attack increases lift increases but so does drag At some point the air cannot follow the wing surface and separates. This causes the wing to rapidly lose lift, creating stall

  20. AERODYNAMICS OF WINGS AERODYNAMIC FORCES ON A WING

  21. AERODYNAMIC LOADS AERODYNAMIC & PHYSICAL LOADS ON AN AIRCRAFT

  22. AERODYNAMICS OF WINGS LIFT AND DRAG

  23. WIND TUNNELS WINDTUNNELS ARE USED TO: DEVELOP EMPIRICAL DESIGN DATA (eg Lift/Drag polars) INVESTIGATE AERODYNAMIC PHENOMENA (eg flutter) DEVELOP AND VERIFY DESIGNS

  24. WINDTUNNELS WRIGHT BROTHERS WIND TUNNEL Critical to the Wright Brothers’ success was their wind tunnel. When they tested their previous design that failed expectations they discovered that its lift was 1/3 of design predictions

  25. WINDTUNNELS WRIGHT BROTHERS WIND TUNNEL

  26. WINDTUNNELS LARGE SCALE WIND TUNNELS

  27. WINDTUNNELS OPTIONS • CLOSED LOOP: • Facilitates changes in altitude (pressure). • Reduces energy consumption. • OPEN LOOP: • Required for engine testing and testing with inlet additives (eg water, contamination, etc. • Ambient • Inlet air heaters & coolers • Exhaust pumps to vary altitude and flight speed. • BLOW DOWN : • Open configuration • Closed configuration

  28. WINDTUNNELS BLOW DOWN WIND TUNNELS

  29. VISUALIZING FLOW FIELDS SCHLIEREN , SHADOW GRAPHS, & LDV USE AIR DENSITY FOR VISUALIZATION

  30. WINDTUNNELS VERTICAL WIND TUNNELS NASA LEWIS (GLENN) 5 FT VERTICAL WIND TUNNEL - 1917

  31. WINDTUNNELS NON - AIRCRAFT APPLICATIONS

  32. WINDTUNNELS AERODYNAMIC DRAG MEASUREMENT ON BUILDINGS USING SCALE MODELS

  33. HURRICANES & TORNADOS WIND LOADS ON STRUCTURES

  34. HURRICANES AND TORNADOES 0 EFFECT OF HIGH WIND SPEED ON HOUSE ROOF LOADS

  35. WINDTUNNELS AERODYNAMICS OF VEHICLES OBJECTIVE: REDUCE DRAG FOR REDUCED FUEL CONSUMPTION AND INCREASED SPEED. AUTOMOBILES, RACE CARS, MOTORCYCLES & TRUCKS

  36. AUTOMOTIVE APPLICATIONS MERCEDES BENZ ENVIRONMENTAL TESTING NASA LANGLEY FULL SCALE TESTING GM WIND TUNNEL

  37. FLOW VISUALIZATION SMOKE STREAMS Smoke streams clearly show flow separation and turbulence – which means higher drag and higher fuel consumption

  38. FLOW VISUALIZATION SPOILER HOW TO PREVENT A CAR FROM BECOMING AN AIRPLANE INVERTED WING

  39. FLOW VISUALIZATION WOOL TUFTS

  40. AERODYNAMICS IN SPORTS SKI JUMPING DOWNHILL RACING SPEED SKATING SKY DIVING BICYCLE RACING GOLF

  41. WINDTUNNELS SKI JUMPING V STYLE CLASSIC STYLE

  42. WINDTUNNELS SKY DIVING MODERN VERTICAL WIND TUNNELS – FOR FUN AND GAMES

  43. WINDTUNNELS RACING APPLICATIONS

  44. AERODYNAMICS OF GOLF WHY DIMPLED GOLFBALLS? In the early days of golf when the balls were smooth some golfers noticed that their old beat up golf balls drove further than new golf balls – hence the design of dimpled ball covers.

  45. AERODYNAMICS OF SPEED SKATING Under Armour and Lockheed Martin designed gear for the 2014 Winter Olympics

  46. AERODYNAMICS OF DRAFTING THE LEADER FIGHTS THE HIGHEST DRAG PEDALING A BICYCLE AT 152 MPH

  47. AERODYNAMICS EVERYONE IN ONE WAY OR ANOTHER IS AFFECTED BY AERODYNAMICS (BUT MOST OF US DO NOT REALIZE IT) THE PHENOMENAE OF AERODYNAMICS AND THE ATTENDANT LAWS OF PHYSICS CAN BE DEMONSTRATED WITH A SIMPLE WIND TUNNEL ITS ADVANTAGE IS THAT IT PROVIDES AN INTERESTING “SEE AND TOUCH” APPROACH WITH CONSIDERABLE OPTIONS FOR STUDENTS TO DEVELOP AN UNDERSTANDING OF BASIC SCIENCE

  48. AERODYNAMICS Dennis Barbeau dennisb@innsolinc.com

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