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Unsteady pressure-sensitive-paint (PSP) measurement in low-speed flow: characteristic mode decomposition and noise floor analysis


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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A :

m × n matrix

A, B :

Stern–Volmer coefficient

D :

Width and depth of square cylinder model

f :


f s :

Frame rate of camera

Δf :

Frequency resolution

I :

Intensity of PSP luminescence

L :


N :

Number of images


Number of images for FFT

P :


ΔP :

Measurement error of PSP




Proper orthogonal decomposition

Re :

Reynolds number

St :

Strouhal number

S XX :

Auto spectral obtained by FFT


Spectral density function

T :


U :

Eigenvector matrix of AAT

U :


U :

Free stream velocity

u :

Left singular vectors

V :

Eigenvector matrix of ATA

v :

Right singular vectors

w :


x :


y :


Σ :

Non-zero singular values of matrix A

σ :

Singular values




Frame per second


Pressure transducer


Mode spectral


Polymer/Ceramic PSP


Pressure-sensitive paint


Power spectral density


Reference condition


Reconstructed value/mode


Root mean square of pressure fluctuations


Signal-to-noise ratio


Singular-value decomposition


Time series




  1. Anyoji M, Numata D, Nagai H, Asai K (2015) Pressure-sensitive paint technique for surface pressure measurement in a low density wind tunnel. J Vis 18(2):297–309

    Article  Google Scholar 

  2. Asai K, Yorita D (2011) Unsteady PSP measurement in low-speed flow—overview of recent advancement at Tohoku University. AIAA paper 2011, 2011-0847

  3. Bell JH, Schairer ET, Lawrence A, Hand LA, Mehta RD (2001) Surface pressure measurements using luminescent coatings. Annu Rev Fluid Mech 33:155–206

    Article  Google Scholar 

  4. Davis T, Edstrand A, Alvi FS, Cattaffesta L, Yorita D, Asai K (2015) Investigation of impinging jet resonant modes using unsteady pressure-sensitive paint measurements. Exp Fluids 56(5):1–13

    Article  Google Scholar 

  5. Fujii S, Numata D, Nagai H, Asai K (2013) Development of ultrafast response anodized aluminum pressure-sensitive paints. In: Proceedings of the 51st AIAA aerospace sciences meeting including the new horizons forum and aerospace exposition, grapevine, Texas, USA, AIAA-2013-0485

  6. Gordeyev S, De Lucca N, Jumper EJ, Hird K, Juliano TJ, Gregory JW, Thordahl J, Wittich DJ (2014) Comparison of unsteady pressure fields on turrets with different surface features using pressure-sensitive paint. Exp Fluids 55:1–20

    Article  Google Scholar 

  7. Gregory JW, Sakaue H, Sullivan JP, Raghu S (2001) Characterization of miniature fluidic oscillator flowfields using porous pressure sensitive paint. In: Proceedings of the ASME fluid engineering division-summer meeting, New Orleans, LA, FEDSM-2001-18058

  8. Gregory JW, Sakaue H, Liu T, Sullivan JP (2014) Fast pressure-sensitive paint for flow and acoustic diagnostics. Annu Rev Fluid Mech 46:303–330

    MathSciNet  Article  Google Scholar 

  9. Kameda M, Seki H, Makoshi T, Amao Y, Nakakita K (2008) Unsteady measurement of a transonic delta wing flow by a novel PSP. In: Proceedings of the 26th AIAA applied aerodynamics conference, AIAA-2008-6418

  10. Kitashima S, Numata D, Asai K (2014) Characterization of pressure-sensitive paint containing ceramic particles. In: Proceedings of the 16th international symposium on flow visualization, Okinawa, Japan, ISFV16-1286

  11. Liu T (2003) Pressure-correction method for low-speed pressure-sensitive paint measurements. AISS J 41:906–911

    Google Scholar 

  12. Liu T, Sullivan JP (2005) Pressure and temperature sensitive paints. Springer, Berlin

    Google Scholar 

  13. Lumley JL (1967) The structure of inhomogeneous turbulence. In: Yaglom AM, Tatarski VL (eds) Atmospheric turbulence and wave propagation. Nauka, Moscow, pp 166–178

    Google Scholar 

  14. Nakakita K (2011) Unsteady pressure measurement on NACA0012 model using global low-speed unsteady PSP technique. In: Proceedings of the 41st AIAA fluid dynamics conference and exhibit, 2011, Honolulu, Hawaii, AIAA 2011-3901

  15. Nakakita K (2013) Detection of phase and coherence of unsteady pressure field using unsteady PSP measurement. In: Proceedings of the AIAA ground testing conference fluid dynamics and co-located conferences, San Duego, CA, AIAA-2013-3124

  16. Nakakita K, Takama Y, Imagawa K, Kato H (2012) Unsteady PSP measurement of transonic unsteady flow field around a rocket fairing model. In: Proceedings of the 28th aerodynamic measurement technology, ground testing, and flight testing conference, Orleans, Louisiana, AIAA-2012-2578

  17. Pandey A, Gregory JW (2015) Dynamic response characteristics of polymer/ceramic pressure-sensitive paint. In: Proceedings of the 53rd aerospace sciences meeting, Kissimmee, Florida, AIAA-2015-0021

  18. Pastuhoff M, Yorita D, Asai K, Alfredsson PH (2013) Enhancing the signal-to-noise ratio of pressure sensitive paint data by singular value decomposition. Meas Sci Technol 24:075301

    Article  Google Scholar 

  19. Peng D, Wang S, Liu Y (2016) Fast PSP measurements of wall-pressure fluctuation in low-speed flows: improvements using proper orthogonal decomposition. Exp Fluids 57:1–17

    Article  Google Scholar 

  20. Sakaue H, Kakisako T, Ishikawa H (2011) Characterization and optimization of polymer-ceramic pressure-sensitive paint by controlling polymer content. Sensors 11(7):6967–6977

    Article  Google Scholar 

  21. Scroggin AM, Slamovich EB, Crafton JW, Lachendo N, Sullivan JP (1999) Porous polymer/ceramic composites for luminescent-based temperature and pressure measurement. Mater Res Soc Proc 560:347–352

    Article  Google Scholar 

  22. Sugimoto T, Kitashima S, Numata D, Nagai H, Asai K (2012) Characterization of frequency response of pressure-sensitive paints. In: Proceedings of the 50th AIAA aerospace sciences meeting including the new horizons forum and aerospace exposition, AIAA-2012-1185

  23. Sugioka Y, Numata D, Asai K, Nakakita K, Koike S, Koga S (2015) Unsteady PSP measurement of transonic buffet on a wing. In: Proceedings of the 53rd AIAA aerospace sciences meeting, kissimmee, Florida, 5–9 January, 2015, AIAA-2015-0025

  24. Sugioka Y, Numata D, Asai K, Koike S, Nakkita K, Nakajima T (2018) Polymer/ceramic pressure-sensitive paint with reduced roughness for unsteady measurement in transonic flow. AIAA J 56(6):2145–2156

    Article  Google Scholar 

  25. Yorita D, Numata D, Nagai H, Asai K (2010) Measuring unsteady low-speed flow phenomena by using a time-series analysis of pressure-sensitive paint images. In: Proceedings of the international symposium on flow visualization, EXCO Daegu, Korea

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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.

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Correspondence to Lin Chen.

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Sugioka, Y., Hiura, K., Chen, L. et al. Unsteady pressure-sensitive-paint (PSP) measurement in low-speed flow: characteristic mode decomposition and noise floor analysis. Exp Fluids 60, 108 (2019).

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