TY - JOUR
T1 - Unsteady pressure-sensitive-paint (PSP) measurement in low-speed flow
T2 - characteristic mode decomposition and noise floor analysis
AU - Sugioka, Yosuke
AU - Hiura, Kodai
AU - Chen, Lin
AU - Matsui, Akitoshi
AU - Morita, Kiyoshi
AU - Nonomura, Taku
AU - Asai, Keisuke
N1 - Funding Information:
This work and the experiments were conducted in the Lab of Experimental Aerodynamics, Tohoku University, Japan. The support from the Talents Program of the Chinese Academy of Sciences (China), the JSPS KAKENHI (No. 16H04582), and the JST-PREST (No. JPMJPR1678) are gratefully acknowledged by the authors.
Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Abstract: Pressure-sensitive-paint (PSP) measurement was conducted for unsteady phenomena at various frequencies up to the order of kHz in low-speed flow to evaluate measurement accuracy of PSP. Pressure fluctuations on the floor surface induced by the Karman vortex were measured by PSP and unsteady pressure transducer. The dominant frequency of the pressure fluctuations is varied from 0.15 to 1.7 kHz by changing the size of the square cylinder. While regions with large pressure fluctuations could be visualized by calculating root mean square of pressure fluctuations from PSP images, the values significantly differed from those measured by pressure transducer. By applying Fast Fourier Transform (FFT), the power spectral density (PSD) at peak frequencies could be obtained within an error of 20%. Singular-value decomposition (SVD) yields a remarkable improvement in signal-to-noise ratio. However, amplitude of pressure fluctuations is changed depending on the way how to select modes. Three mode-selection methods for SVD filtering/reconstruction analysis are proposed in this study which show good improvement compared with convection method and are proved capable of extracting characteristic behaviors of the flow phenomena even below the noise floor.
AB - Abstract: Pressure-sensitive-paint (PSP) measurement was conducted for unsteady phenomena at various frequencies up to the order of kHz in low-speed flow to evaluate measurement accuracy of PSP. Pressure fluctuations on the floor surface induced by the Karman vortex were measured by PSP and unsteady pressure transducer. The dominant frequency of the pressure fluctuations is varied from 0.15 to 1.7 kHz by changing the size of the square cylinder. While regions with large pressure fluctuations could be visualized by calculating root mean square of pressure fluctuations from PSP images, the values significantly differed from those measured by pressure transducer. By applying Fast Fourier Transform (FFT), the power spectral density (PSD) at peak frequencies could be obtained within an error of 20%. Singular-value decomposition (SVD) yields a remarkable improvement in signal-to-noise ratio. However, amplitude of pressure fluctuations is changed depending on the way how to select modes. Three mode-selection methods for SVD filtering/reconstruction analysis are proposed in this study which show good improvement compared with convection method and are proved capable of extracting characteristic behaviors of the flow phenomena even below the noise floor.
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U2 - 10.1007/s00348-019-2755-9
DO - 10.1007/s00348-019-2755-9
M3 - Article
AN - SCOPUS:85066943835
SN - 0723-4864
VL - 60
JO - Experiments in Fluids
JF - Experiments in Fluids
IS - 7
M1 - 108
ER -