2014 Fiscal Year Annual Research Report
| Project/Area Number |
14F04756
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| Research Institution | Tohoku University |
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Principal Investigator |
浅井 圭介 東北大学, 工学(系)研究科(研究院), 教授 (40358669)
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| Co-Investigator(Kenkyū-buntansha) |
PASTUHOFF Markus 東北大学, 工学(系)研究科(研究院), 外国人特別研究員
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| Project Period (FY) |
2014-04-25 – 2016-03-31
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| Keywords | Fluid Dynamics / Magnetic Suspension / Pressure Sensitive Paint |
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| Outline of Annual Research Achievements |
One major goal of the magnetic suspension and balance system (MSBS) is to enable measurements in non-stationary conditions where the model is made to move in order to investigate the transitional behavior of real flight. In the MSBS the attainable frequencies are currently limited by the control system to a few tens of Hertz which makes the performance of PSPs in this region especially important for the purposes.
For the purpose of accurately characterizing and calibration PSP in the frequency ranges appropriate for MSBS measurements a calibration system has been designed. The device has been designed such that PSP can be calibrated with respect to pressure, temperature, and frequency independently of each other and in the approximate ranges of 0-2 kPa, 5-50°C, and 0.1-250 Hz respectively. By stepping through a range of fixed pressure frequencies and fitting the PSP output to a reference pressure transducer gain and phase diagrams can be produced for each temperature.
In parallel to the design of the calibration system previously created filtering methods for low-speed unsteady PSP by Pastuhoff has been further developed for filtering of so called life-time based PSP. Spatiotemporal life-time PSP is a potential candidate for use with the MSBS system. The filtering method itself is based on singular vector decomposition (SVD) which maps a data set into an orthogonal set of vectors which are sorted in an energy optimal sense. These spatiotemporal correlating structures can be separated from non-correlating parts.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In the fall of 2014, a 0.3 m magnetic suspension and balance system (MSBS) test section was introduced in the Experimental Aerodynamic Laboratory of Tohoku University. The aim of the MSBS project is to enable non-intrusive dynamic wind-tunnel measurements. A second aim is to facilitate the concurrent use of pressure sensitive paint (PSP) in the system. One obstacle encountered is the lack of calibration data for PSP in the frequency ranges suitable for use in the MSBS, in the order of a few Hertz. Currently calibration methods for static cases as well as frequency ranges from a few hundred to thousands of Hertz exist. This is considered a major problem not only within the MSBS project but for the application of the PSP method itself. To meet this need, a calibration device for lower frequencies has been designed by Pastuhoff and its manufacturing is nearing completion. The device has been designed such that PSP can be calibrated with respect to pressure, temperature, and frequency independently of each other and in the approximate ranges of 0-2 kPa, 5-50°C, and 0-250 Hz respectively. Given the time limit of Pastuhoff's project, effort has been made to as far as possible automate and simplify the calibration method in order for a simpler transfer of knowledge.
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| Strategy for Future Research Activity |
It was mentioned that a problem for the combination of the MSBS with measurements using PSP was hindered by the lack of calibration data in frequency ranges applicable to the MSBS. However, this is not the only problem encountered in combining the two techniques. The current MSBS setup uses an optical system to detect the model position and careful though has to made so that the optical frequencies of the PSP does not interfere with this system, and vice versa. For successful use of the two techniques a number of parameters are to be evaluated, e.g. model position detectors and optimal control methods, with Pastuhoff's expertise on mechatronics. Apart for his work on MSBS-PSP system integration, it is also planned to have Pastuhoff assist in a measurement campaign involving the dynamic response of pressure measured through tubing for road vehicle application using the developed calibration chamber. Furthermore, Pastuhoff is expected to assist in applying the singular value decomposition to a number of spatiotemporal data sets acquired by PSP.
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Research Products
(1 results)
