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Powered Resonance Tubes: Resonance Characteristics and Actuation Signal Directivity
Title
Powered Resonance Tubes: Resonance Characteristics and Actuation Signal Directivity
Creator
Sarpotdar, S., Raman, G., Cain, A. B.
Date
2005-12
Publisher
Springer
Description
The powered resonance tube (PRT) actuator and its variants are new developments in active flow control (AFC) technology. The PRT is attractive...
Show moreThe powered resonance tube (PRT) actuator and its variants are new developments in active flow control (AFC) technology. The PRT is attractive because it has no moving parts and can produce acoustic tones that have amplitudes greater than 150 dB over a large frequency bandwidth. The first part of this paper deals with the resonance characteristics of the PRT as a function of the operating parameters such as jet-to-tube spacing (Sp), tube depth (d), and nozzle pressure ratio (NPR). It was found that: (1) at low NPR (3.33), the PRT resonates at discrete combinations of spacing and depth. (2) Using theoretical estimates for predicting shock cell lengths, one could observe a correlation between the theoretical prediction for shock cell length and the spacing at which the PRT resonates. (3) At high NPR (4.29), for a fixed depth, the PRT resonates at virtually all spacings. (4) The frequency at which the PRT resonates remains approximately constant, regardless of spacing. The second part of the study focused on examining the directivity of the acoustic radiation from the PRT-significant for developing orientation strategies of the PRT with respect to the target flow in the end application. The directivity of the fundamental PRT tone and that of its harmonics were studied for a variety of resonance frequencies, both separately as well as cumulatively. It was found that the fundamental part of the actuation signal radiated predominantly in the downstream direction of the jet for low resonance frequencies. As the resonance frequency was increased from 3 to 12 kHz, the directivity changed from downstream of the jet to vertically upward, and finally upstream of the jet at the higher frequencies.
http://dx.doi.org/10.1007/s00348-005-0041-5
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Assessing Graduate Student Progress in Engineering Ethics
Title
Assessing Graduate Student Progress in Engineering Ethics
Creator
Davis, Michael, Feinerman, Alan
Date
2010-11-10, 2011
Publisher
Springer
Description
Under a grant from the National Science Foundation, the authors (and others) undertook to integrate ethics into graduate engineering classes...
Show moreUnder a grant from the National Science Foundation, the authors (and others) undertook to integrate ethics into graduate engineering classes at three universities—and to assess success in a way allowing comparison across classes (and institutions). This paper describes the attempt to carry out that assessment. Standard methods of assessment turned out to demand too much class time. Under pressure from instructors, the authors developed an alternative method that is both specific in content to individual classes and allows comparison across classes. Results are statistically significant for ethical sensitivity and knowledge. They show measurable improvement in a single semester.
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'Ain't No One Here But Us Social Forces' : Constructing the Social Responsibility of Engineers.
Title
'Ain't No One Here But Us Social Forces' : Constructing the Social Responsibility of Engineers.
Creator
Davis, Michael
Date
2011-04, 2011-06
Publisher
Springer
Description
There are many ways to avoid responsibility, for example, explaining what happens as the work of the gods, fate, society, or the system. For...
Show moreThere are many ways to avoid responsibility, for example, explaining what happens as the work of the gods, fate, society, or the system. For engineers, “technology” or “the organization” will serve this purpose quite well. We may distinguish at least nine (related) senses of “responsibility”, the most important of which are: (a) responsibility-as-causation (the storm is responsible for flooding), (b) responsibility-as-liability (he is the person responsible and will have to pay), (c) responsibility-as-competency (he’s a responsible person, that is, he’s rational), (d) responsibility-as-office (he’s the responsible person, that is, the person in charge), and (e) a responsibility-as-domain-of-tasks (these are her responsibilities, that is, the things she is supposed to do). For all but the causal sense of responsibility, responsibility may be taken (in a relatively straightforward sense)—and generally is. Why then would anyone want to claim that certain technologies make it impossible to attribute responsibility to engineers (or anyone else)? In this paper, I identify seven arguments for that claim and explain why each is fallacious. The most important are: (1) the argument from “many hands”, (2) the argument from individual ignorance, and (3) the argument from blind forces. Each of these arguments makes the same fundamental mistake, the assumption that a certain factual situation, being fixed, settles responsibility, that is, that individuals, either individually or by some group decision, cannot take responsibility. I conclude by pointing out the sort of decisions (and consequences) engineers have explicitly taken responsibility for and why taking responsibility for them is rational, all things considered. There is no technological bar to such responsibility.
Science and Engineering Ethics.
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“Broader Impacts” or “Responsible Research and Innovation”? A Comparison of Two Criteria for Funding Research in Science and Engineering
Title
“Broader Impacts” or “Responsible Research and Innovation”? A Comparison of Two Criteria for Funding Research in Science and Engineering
Creator
Davis, Michael, Laas, Kelly
Date
2013-10, 2013-10
Publisher
Springer
Description
Our subject is how the experience of Americans with a certain funding criterion, “broader impacts” (and some similar criteria) may help in...
Show moreOur subject is how the experience of Americans with a certain funding criterion, “broader impacts” (and some similar criteria) may help in efforts to turn the European concept of Responsible Research and Innovation (RRI) into a useful guide to funding Europe’s scientific and technical research. We believe this comparison may also be as enlightening for Americans concerned with revising research policy. We have organized our report around René Von Schomberg’s definition of RRI, since it seems both to cover what the European research group to which we belong is interested in and to be the only widely accepted definition of RRI. According to Von Schomberg, RRI: “… is a transparent, interactive process by which societal actors and innovators become mutually responsive to each other with a view to the (ethical) acceptability, sustainability and societal desirability of the innovation process and its marketable products (in order to allow a proper embedding of scientific and technological advances in our society).” While RRI seeks fundamental changes in the way research is conducted, Broader Impacts is more concerned with more peripheral aspects of research: widening participation of disadvantaged groups, recruiting the next generation of scientists, increasing the speed with which results are used, and so on. Nevertheless, an examination of the broadening of funding criteria over the last four decades suggests that National Science Foundation has been moving in the direction of RRI.
Sponsorship: European Community’s Seventh Framework Programme grant number 321400.
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