1 00:00:00,000 --> 00:00:07,600 Oh, great. You're just in time. Everybody, let me introduce you to Brenda Sullivan and 2 00:00:07,600 --> 00:00:13,280 Rich Silcox. We're here at NASA Langley in a building where they do acoustical research. 3 00:00:13,280 --> 00:00:17,400 Let's go here first to Rich. You are a senior research engineer, right? 4 00:00:17,400 --> 00:00:18,400 Correct. 5 00:00:18,400 --> 00:00:23,000 All right. And Brenda, hmm, I'm going to get this name wrong. Brenda, you are a psychoacoustician. 6 00:00:23,000 --> 00:00:27,760 Now, can you correct my wording and then tell me a little bit about what that is? 7 00:00:27,760 --> 00:00:34,600 Well, I'm a psychoacoustician. Psychoacoustician is somebody who designs, conducts, and analyzes 8 00:00:34,600 --> 00:00:38,360 tests to study the psychological effects of noise on people. 9 00:00:38,360 --> 00:00:42,520 Oh, psychological effects. Now, that's kind of interesting. And Rich, how about you? Can 10 00:00:42,520 --> 00:00:46,080 you describe for us just what exactly is a senior research engineer? 11 00:00:46,080 --> 00:00:50,720 Well, Shelly, there's a lot of noise research that goes on here relating to aircraft noise. 12 00:00:50,720 --> 00:00:55,920 And I work with researchers both here and at NASA Glenn in Ohio and NASA Ames in California 13 00:00:55,920 --> 00:01:00,760 to come up with ways to reduce the noise that aircraft make. The word acoustics means 14 00:01:00,760 --> 00:01:05,640 the scientific study of sound and how the qualities of space affect sound to transmit 15 00:01:05,640 --> 00:01:08,240 well or poorly. 16 00:01:08,240 --> 00:01:12,160 Why don't we begin with the research that Brenda's doing? Brenda, why don't you introduce 17 00:01:12,160 --> 00:01:14,320 Shelly to your fellow sound researcher? 18 00:01:14,320 --> 00:01:16,840 Certainly. Shelly, meet Fred the Head. 19 00:01:16,840 --> 00:01:17,840 This is Fred? 20 00:01:17,840 --> 00:01:23,120 This is Fred. Fred and his friend Norm here are essentially my research. Testing for noise 21 00:01:23,240 --> 00:01:28,720 starts with deciding what aspect of noise to study. For instance, the sound in a community 22 00:01:28,720 --> 00:01:32,400 near an airport or the noises inside an actual airplane. 23 00:01:32,400 --> 00:01:37,320 See, that's where Norm comes in. I take him up in the air inside the airplane so he can 24 00:01:37,320 --> 00:01:42,440 record the noises that are in there in flight. See, he's got a microphone in each ear. They're 25 00:01:42,440 --> 00:01:45,840 kind of hard to see on Norm. They're easier to see on Fred. Let me show you. 26 00:01:45,840 --> 00:01:46,840 Okay. 27 00:01:46,840 --> 00:01:47,840 Ouch! 28 00:01:47,840 --> 00:01:51,360 It's all right. He's used to that sort of treatment. See, he's got a mic in there. It's 29 00:01:51,360 --> 00:01:53,920 hard to see. Let me take his skull off. 30 00:01:53,920 --> 00:01:54,920 Oh, wow. 31 00:01:54,920 --> 00:01:57,840 See, he has a microphone in each ear. 32 00:01:57,840 --> 00:02:01,880 Anyway, these little microphones record the sound that's heard by each ear just as you 33 00:02:01,880 --> 00:02:07,120 would hear it yourself. I take these binaural recordings I make with Norm and bring them 34 00:02:07,120 --> 00:02:11,040 back to the lab. I can edit them on the computer and play them back to the people who come 35 00:02:11,040 --> 00:02:16,680 in to act as subjects in my tests. For instance, I can take some of the tones made by the propellers 36 00:02:16,680 --> 00:02:21,160 of a plane and reduce them. And people can tell me if they prefer the reduced versions 37 00:02:21,160 --> 00:02:25,120 and how much they prefer them so that we can predict their reactions to future noises. 38 00:02:25,120 --> 00:02:26,120 Oh, how interesting. 39 00:02:26,120 --> 00:02:32,000 Shelly, if you'd like, I can arrange to show you NASA's 757 research aircraft. And I can 40 00:02:32,000 --> 00:02:36,040 show you the physics involved in producing the sound and how one goes about controlling 41 00:02:36,040 --> 00:02:37,040 the sound. 42 00:02:37,040 --> 00:02:39,800 Oh, man, that would be so cool. I know I'd be interested. I'm sure the viewers would 43 00:02:39,800 --> 00:02:43,640 be interested in seeing a real live NASA jumbo jet research plane. 44 00:02:51,640 --> 00:02:57,360 Shelly, this is the NASA 757 in which we conduct various types of research. NASA has a ten-year 45 00:02:57,360 --> 00:03:02,240 goal to reduce noise impact from aircraft so that communities hear one half the noise 46 00:03:02,240 --> 00:03:06,720 that they heard in 1997. The amount of noise reduction is similar to the difference between 47 00:03:06,720 --> 00:03:11,960 heavy traffic noise and light traffic noise. The noise impact reduction effort is led by 48 00:03:11,960 --> 00:03:17,320 NASA Langley Research Center and is conducted in close partnership with NASA Glenn Research 49 00:03:17,320 --> 00:03:23,400 Center in Ohio and NASA Ames Research Center in California, along with help from academia, 50 00:03:23,400 --> 00:03:25,040 industry and the FAA. 51 00:03:25,040 --> 00:03:30,440 Wow, this aircraft is huge. Where do you even begin to start to find the many sources of 52 00:03:30,440 --> 00:03:32,400 noise that must come from this aircraft? 53 00:03:32,400 --> 00:03:37,200 In some modern aircraft like this 757, a lot of noise is generated from the air turbulence 54 00:03:37,200 --> 00:03:43,840 created by the wing flaps, slats and landing gear slicing through the air. To control this 55 00:03:43,840 --> 00:03:48,600 type of noise, we use computers to create detailed models of the airflow over these 56 00:03:48,600 --> 00:03:52,800 surfaces and look for ways to smooth out the flow and reduce the turbulence. 57 00:03:52,800 --> 00:03:57,960 Shelly, of course, most of the noise is produced by the jet engine. Modern jet engines have 58 00:03:57,960 --> 00:04:02,680 these large fans that move large volumes of air through the engines. However, the fan 59 00:04:02,680 --> 00:04:07,680 itself produces what we call fan tones. This type of noise is reduced by treating the inlet 60 00:04:07,680 --> 00:04:12,520 and exhaust duct with special acoustic liners, sort of like towels for office ceilings. 61 00:04:12,520 --> 00:04:18,280 And Shelly, the biggest noise problem we have is that of jet exhaust noise. And working 62 00:04:18,280 --> 00:04:21,000 with us in jet exhaust noise is Martha Brown. Hi, Martha. 63 00:04:21,000 --> 00:04:22,000 Hi, Rich. 64 00:04:22,000 --> 00:04:24,000 Hi, Martha. Hi, Shelly. 65 00:04:24,000 --> 00:04:28,160 Martha, Shelly has a particular problem in noise abatement. I was wondering if you could 66 00:04:28,160 --> 00:04:29,520 explain to Martha what it is. 67 00:04:29,520 --> 00:04:34,320 Yeah, thanks, Rich. My problem is that I'm trying to get some pointers on how to reduce 68 00:04:34,320 --> 00:04:39,040 noise for my friend Van and his band, The Noodles. They rehearse in a garage. It seems 69 00:04:39,040 --> 00:04:43,720 that their rehearsals are disturbing the neighbor as he's trying to take a nap. So we're trying 70 00:04:43,720 --> 00:04:47,440 to figure out how can we reduce the noise or the sound coming out of the garage. Do 71 00:04:47,440 --> 00:04:48,440 you think you can help? 72 00:04:48,440 --> 00:04:52,200 I'll be glad to help. But first, let me tell you a little bit about myself and what I do 73 00:04:52,200 --> 00:04:53,200 at NASA Langley. 74 00:04:53,200 --> 00:04:54,200 Okay. 75 00:04:54,200 --> 00:04:58,640 I work as an engineer in the Jet Noise Laboratory. I study ways to change the air coming out 76 00:04:58,640 --> 00:05:04,240 of a jet with the hope of reducing noise created by this air. High-speed air is needed to 77 00:05:04,240 --> 00:05:09,560 move an airplane forward. I work with a team of engineers to invent ways to change the 78 00:05:09,560 --> 00:05:13,240 speed of the air exiting the jet by jet mixing. 79 00:05:13,240 --> 00:05:15,760 So just how do you increase jet mixing? 80 00:05:15,760 --> 00:05:25,760 Well, Shelly, we use non-round shapes like this rectangle nozzle, this elliptical nozzle, 81 00:05:25,760 --> 00:05:27,120 and also this corrugated nozzle. 82 00:05:27,120 --> 00:05:30,560 Oh, now this reminds me of a flower with petals. 83 00:05:30,560 --> 00:05:33,880 I see what you mean. But in fact, they're called lobes. 84 00:05:33,880 --> 00:05:34,880 Lobes? 85 00:05:34,880 --> 00:05:40,720 Yes. And also we may change the round nozzle and how it looks by adding tabs at the ends 86 00:05:40,720 --> 00:05:41,720 that you see here. 87 00:05:41,720 --> 00:05:47,320 Oh, now these tabs look like shark teeth. So what other ways do you have to reduce noise? 88 00:05:47,320 --> 00:05:55,720 Well, Shelly, we use materials to line the inside of the nozzle. You see, this is called 89 00:05:55,720 --> 00:06:01,920 a liner. And what it's used to do is to absorb the sound before it exits the nozzle. 90 00:06:01,920 --> 00:06:02,920 Like a muffler? 91 00:06:02,920 --> 00:06:03,920 Yes. 92 00:06:03,920 --> 00:06:08,640 Okay, let's go back to Van now. What one point might you make back to Van that could help 93 00:06:08,640 --> 00:06:10,920 him with his problem? 94 00:06:10,920 --> 00:06:15,600 I recommend that he buy ceiling tiles to line the ceiling of his garage. 95 00:06:15,600 --> 00:06:16,600 Oh, okay. 96 00:06:16,600 --> 00:06:20,600 And Shelly, he can install carpet on the floor and draperies on the windows to help reduce 97 00:06:20,600 --> 00:06:21,600 the sound. 98 00:06:21,600 --> 00:06:26,760 Oh, Rich and Martha, that's great sound advice. And I will share that back with Van. Thank 99 00:06:26,760 --> 00:06:27,760 you so much. 100 00:06:27,760 --> 00:06:28,760 You're very welcome. 101 00:06:28,760 --> 00:06:32,440 All right. And to the rest of you, gang, I'm going to send you to find Van and see what 102 00:06:32,440 --> 00:06:35,960 he's up to. Meanwhile, I'm going to head back to the NASA Connect studio and get ready for 103 00:06:35,960 --> 00:06:39,640 our special guest. And if you haven't thought of some questions, think about some because 104 00:06:39,640 --> 00:06:43,520 in a moment, you'll be able to call in with your questions. I'll see you back at the studio.