Skip to main content

Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods


Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa\(^2\) (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13


  1. Ali MY, Pandey A, Gregory JW (2016) Dynamic mode decomposition of fast pressure sensitive paint data. Sensors 16:862.

    Article  Google Scholar 

  2. Asai K, Yorita D (2011) Unsteady PSP measurement in low-speed flow – Overview of recent advancement at Tohoku University. In: Proceeding of the 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, AIAA 2011-847.

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

    Article  MATH  Google Scholar 

  4. Bendat JS, Piersol AG (1980) Engineering applications of correlation and spectral analysis. Wiley, New York

    MATH  Google Scholar 

  5. Desquesnes G, Terracol M, Sagaut P (2007) Numerical investigation of the tone noise mechanism over laminar airfoils. J Fluid Mech 591:155–182

    Article  MATH  Google Scholar 

  6. Doolan CJ, Moreau DJ (2016) Flow-induced noise generated by sub-boundary layer steps. Exp Therm Fluid Sci 72:47–58

    Article  Google Scholar 

  7. Gabriel C, Müller S, Ullrich F, Lerch R (2014) A new kind of sensor array for measuring spatial coherence of surface pressure on a car’s side window. J Sound Vib 333:901–915.

    Article  Google Scholar 

  8. Gade S, Hald J (2012) Noise source identification with increased spatial resolution in automotive industry. J Acoust Soc Am 131:3220.

    Article  Google Scholar 

  9. Goldman S (1999) Vibration spectrum analysis: a practical approach, 2nd edn. Industrial Press, New York

    Google Scholar 

  10. Gregory JW, Asai K, Kameda M, Liu T, Sullivan JP (2008) A review of pressure-sensitive paint for high-speed and unsteady aerodynamics. J Aerosp Eng 222:249–290.

    Google Scholar 

  11. 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  MATH  Google Scholar 

  12. Hutcheson FV, Brooks TF (2002) Measurement of trailing edge noise using directional array and coherent output power methods. In: Proceedings of the 8th AIAA/CEAS Aeroacoustics Conference, AIAA-2002-2472.

  13. Kameda M, Tezuka N, Hangai T, Asai K, Nakakita K, Amao Y (2004) Adsorptive pressure-sensitive coatings on porous anodized aluminum. Meas Sci Technol 15:489–500

    Article  Google Scholar 

  14. Kameda M, Tabei T, Nakakita K, Sakaue H, Asai K (2005) Image measurements of unsteady pressure fluctuation by a pressure-sensitive coating on porous anodized aluminum. Meas Sci Technol 16:2517–2524

    Article  Google Scholar 

  15. Kameda M, Yoshida M, Sekiya T, Nakakita K (2015) Humidity effects in the response of a porous pressure-sensitive paint. Sens Actuators B Chem 208:399–405

    Article  Google Scholar 

  16. Kido K (2015) Digital fourier analysis: fundamentals. Springer, New York

    MATH  Google Scholar 

  17. Krause J, Gallman JM, Moeller MJ, White RD (2014) A microphone array on a chip for high spatial resolution measurements of turbulence. IEEE J Microelectrochem Syst 23:1164–1181.

    Article  Google Scholar 

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

    Google Scholar 

  19. Marple SL (1987) Digital spectral analysis with applications. Prentice-Hall, New Jersey

    Google Scholar 

  20. McAlpine A, Nash E, Lowson M (1999) On the generation of discrete frequency tones by the flow around an aerofoil. J Sound Vib 222:753–779

    Article  Google Scholar 

  21. Mérienne M-C, Molton P, Bur R, Le Sant Y (2015) Pressure-sensitive paint application to an oscillating shock wave in a transonic flow. AIAA J 53:3208–3220.

    Article  Google Scholar 

  22. 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, AIAA 2011-3901.

  23. Nakakita K (2013) Phase delay and correlation area detection of unsteady pressure field using unsteady PSP measurement. In: Proceedings of AIAA Ground Testing Conference, AIAA 2013–3124:

  24. Nash E, Lowson M, McAlpine A (1999) Boundary layer instability noise on aerofoils. J Fluid Mech 382:27–61

    Article  MATH  Google Scholar 

  25. 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 

  26. Peng D, Jiao L, Sun Z, Gu Y, Liu Y (2016a) Simultaneous PSP and TSP measurements of transient flow in a long-duration hypersonic tunnel. Exp Fluids 57:188

    Article  Google Scholar 

  27. Peng D, Wang S, Liu Y (2016b) Fast PSP measurements of wall pressure fluctuation in low speed flows: improvements using proper orthogonal decomposition. Exp Fluids 57:45.

    Article  Google Scholar 

  28. Piet J-F, Elias G, Lebigot P (1999) Localization of acoustic source from a landing air-craft with a microphone array. In: Proceedings of 5th AIAA/CEAS Aeroacoustics Conference and Exhibit, Aeroacoustics Conferences, AIAA-1999-1811.

  29. Plogmann B, Herrig A, Würz W (2013) Experimental investigations of a trailing edge noise feedback mechanism on a NACA 0012 airfoil. Exp Fluids 54:1480

    Article  Google Scholar 

  30. Sakaue H, Tabei T, Kameda M (2006) Hydrophobic monolayer coating on anodized aluminum pressure-sensitive paint. Sens Actuators B Chem 119:504–511

    Article  Google Scholar 

  31. Siller HA (2012) Localisation of sound sources on aircraft in flight. In: Proceedings of ASME 2012 Noise Control and Acoustics Division Conference at InterNoise 2012, Paper No. NCAD2012-0575, pp. 193-202; 10 pages.

  32. Yorita D, Nagai H, Asai K, Narumi T (2010) Unsteady PSP technique for measuring naturally-disturbed periodic phenomena. In: Proceedings of the 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, AIAA 2010-307.

Download references


This work was financially supported by JSPS KAKENHI under Grant numbers 2528929 and 16H04265.

Author information



Corresponding author

Correspondence to Masaharu Kameda.

Additional information

Publisher's Note

Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Noda, T., Nakakita, K., Wakahara, M. et al. Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods. Exp Fluids 59, 94 (2018).

Download citation