Aerodynamics Overview

Transcription

1 Aerodynamics Overview

2 Aerodynamics a branch of physics concerned with the study of air as it moves around objects. Answer question 1 on the worksheet.

3 Many things we take for granted are the result of efforts in aerodynamics.

4 Transportation is a system or method for moving people or goods from place to place. The use of aerodynamic principles have helped us to design better transportation systems that are more fuel efficient and capable of greater speeds. Answer question 2 on the worksheet.

5 These design improvements have resulted in energy more conservation and a cleaner environment. Answer question 3 on the worksheet.

6 Other things have benefited from the study of aerodynamics. Tall buildings for instance, must Wind be able to resist large wind forces. forces are the biggest challenge for engineers when designing buildings. Answer question 4 on the worksheet.

7 When an improperly designed building is lean deflected by wind, it will in the direction of the wind, causing the weight of the building to be off center. This is dangerous because it could fall over. Answer question 5 on the worksheet.

8 buildings Today s are designed to resist large wind forces. Some are even aerodynamically shaped to help with these wind forces. Answer question 6 on the worksheet.

9 The tallest building in the U.S. is the Tower in Chicago. It was formally known as the Sears Tower and is 1,450 feet high and 108 Willis stories. Answer question 7 on the worksheet.

10 Sports have also been affected by aerodynamic designs. Speed skiing is a competitive sport where skiers can reach speeds over 150 mph. The helmets worn by speed skiers have to provide protection but also be aerodynamic to achieve higher speeds. Answer question 8 on the worksheet.

11 Bicyclists have been using aerodynamic techniques, such as riding in close packs for many years. This cuts down on wind resistance and help the cyclists conserve energy. Cyclists also lean down and wear aerodynamic helmets to increase their speed and reduce drag. Answer question 9 on the worksheet.

12 Engineers use aerodynamic principles to improve the performance of cars and planes by reducing drag. Answer question 10 on the worksheet.

13 Drag is a force opposing the forward motion of an object. Answer question 1a on the worksheet.

14 As an object moves through the air, the shape surface and features of the object produce drag. Answer question 12 on the worksheet.

15 Drag is caused by the shape of an object. Objects that are square will create a lot of drag as they move through the air. The more square the object the greater the drag. Answer question 13 on the worksheet.

16 The Drag Meter shows that the square object measures high drag. The shape has lower drag. triangle Answer question 14 on the worksheet.

17 Which shape has the most drag? A. B. C. D. E. Answer question 15 on the worksheet.

18 Friction takes place in a thin layer of air surrounding the surface of an object. Friction is caused by the collision of molecules between the moving object and the air. Air friction around objects causes drag. Answer question 16 on the worksheet.

19 The rougher the surface of the object, the greater the friction. Answer question 17 on the worksheet.

20 This object is almost smooth and measures This object is almost smooth and measures low on the Friction Meter. Objects that are smooth have less friction. low on the Friction Meter. Objects that are smooth have less friction. Answer question 18 on the worksheet.

21 The surface changed and is now rougher. The The surface changed and is now rougher. The Friction Meter show that this object has greater friction than the smooth object. Friction Meter show that this object has greater friction than the smooth object.

22 This object is very rough. It has the greatest amount of Friction. Remember the rougher the surface the greater the friction. Answer question 19 on the worksheet.

23 Streamlining is shaping an object so that it has the smallest amount of drag when it moves through the air. When streamlining an object, such as a car, designers want the air to flow in a straight line. The object on the right is more streamlined because the air flows smoothly around it. Answer question 20 on the worksheet.

24 Many things, such as boats, trains, buildings, bridges sports, and are affected by aerodynamic principles. Answer question 21 on the worksheet.

25 Until the early 1970 s, car shapes were determined by style. Aerodynamics played no role in car design. For over 30 years now, car designers have been using aerodynamic principles to improve cars.

26 In order to make cars go faster, automobile manufacturers used bigger. However, these cars used large amounts fuel of. engines Answer question 22 on the worksheet.

27 The oil shortages of the mid 1970 s made these expensive types of cars to to own. This forced automobile manufactures to redesign more fuel efficient cars. Answer question 23 on the worksheet.

28 Part of this effort included redesigning cars with better aerodynamic shapes. This resulted in cars with drag less, which means greater speeds and better fuel mileage. These aerodynamic designs developed into the streamline shapes we see today. Answer question 24 on the worksheet.

29 Lift and Airfoils

30 Early aviation pioneers experimented with model wings and aircraft. These experiments helped them realize that an airplane not only had to overpower the force of drag, but also had to create lift

31 Lift is an upward force that causes a plane to rise by overcoming gravity. Answer question 25 on the worksheet.

32 Bernoulli s Bernoulli s Principle states that as Principle the speed states of a fluid, such as air increases, its pressure that will decrease. as the Let s try speed this with increases, the fan. its pressure will decrease. Let s try this with the fan. Answer question 26 on the worksheet.

33 On low speed the air pressure is. high On Low speed the air pressure is high. Answer question 27 on the worksheet.

34 On High speed the air pressure is the lowest. As the speed of air increases the pressure decreases. Answer question 28 on the worksheet.

35 On low speed the pressure was higher. As the air moves, faster the pressure drops. Remember on Low speed the air pressure was the highest. Answer question 29 on the worksheet.

36 Early inventors realized that objects would move from high pressure areas to pressure areas. low Answer question 30 on the worksheet.

37 What happens if you blow air over the top of this paper?

38 Blowing air over the paper increases the speed of the air and, decreases the air pressure. Because the still air under the paper is at a higher pressure than the moving air over the paper, the paper will lift upwards from the high pressure area toward the low pressure area. Answer question 31 on the worksheet.

39 Wings are designed to take advantage of Bernoulli s Principle. Wings are shaped into airfoils, where the top of the wind curves pwards and is longer than the bottom of the wing. Answer question 32 on the worksheet.

40 Air must travels a distance over the top of the wing than the bottom. This forces the air to move faster over the top, resulting in a lower pressure area. Because the bottom of the wing is at a higher pressure, the wing lifts up toward the low pressure area. Low Pressure longer High Pressure Answer question 33 on the worksheet.

41 Overall lift of a wing can be increased even more by inclining the wing. The incline of a angle wing is called the of attack. Answer question 34 on the worksheet.

42 The two things that give greater lift is using an angle of attack and an airfoil shape. Answer question 35 on the worksheet.

43 buildings A longer path = faster air = low pressure Answer questions 36 and 37 on the worksheet.

44 Aerospace Overview

45 Aerospace is technology that deals with flight. Aerospace transportation deals with moving things through the earth s. atmosphere Answer question 38 on the worksheet.

46 On December 17, 1903, Orville and Wilbur Wright flew the first heavier than air, powered airplane. It took years of problem solving for them to complete the 12 second flight that covered 120 feet. Answer question 39 on the worksheet.

47 Today, less than 100 years later, we depend on aerospace technology in many ways. Humans have even traveled to the moon.

48 There are four basic forces that affect flight through the earth s atmosphere. Answer question 40 on the worksheet.

49 Thrust is a force that propels the airplane forward. Thrust is generally provided by the engine or a propeller attached to the engine. Answer question 41 on the worksheet.

50 Drag is the force that is opposite thrust. The leading surfaces of the plane bump into molecules as it moves through the air. This causes drag. Drag and friction things down. slows Answer question 42 on the worksheet.

51 Lift is the force that opposes gravity. If there is enough lift to overcome gravity, flight is possible. Answer question 43 on the worksheet.

52 Gravity is the force that pulls all things toward the center of the earth. Anything that flies must overcome the force of gravity. Answer question 44 on the worksheet.

53 Answer questions on the worksheet.

54 Bernoulli s Principle states that as the speed increases, the pressure decreases. The air passing over the top of the wing moves faster than the air passing under the wing. The difference in air speed causes a change in pressure. The fast moving air has pressure than the slow moving air. The higher air pressure under the wing pushes, or the wing upward. lifts Answer question 49 on the worksheet.

55 wings The on the airplane create lift. The wing carries the weight of the airplane during flight. Answer question 50 on the worksheet.

56 stomp You are going to make a rocket. The thrust is created from air pressure. Answer question 51 on the worksheet.

57 Something powered by air is pneumatic Something powered by air is called called. pneumatic. are powered by air. Many devices are powered by air. Answer question 52 on the worksheet.

58 Newton s Third Law of Motion states that for every action there is an equal and opposite. reaction Newton s Third Law of Motion The states air rushes out of the end of that for every action there is an the rocket equal and (action) opposite reaction. the reaction is for the rocket to move. forward Answer question 53 on the worksheet.

59 streamlined A object is smooth and curved to reduce A streamlined drag. object You is want smooth your and curved to reduce drag. You rocket to be streamlined so want your rocket to be streamlined it goes so it goes faster and farther. Answer question 54 on the worksheet.

60 Motion Friction friction The force of is opposite the direction of motion. Friction causes objects to slow down. Answer question 55 on the worksheet.

61 Body Bottle of Air 61. Stomp Rocket Parts Label the parts for questions

62 You are going to watch a video to learn how to build a stomp rocket.