title: Measurement of transient acoustic fields using a single-shot pressure-sensitive paint system.
abstract: A pressure-sensitive paint (PSP) system capable of measuring high-frequency acoustic fields with non-periodic, acoustic-level pressure changes is described. As an optical measurement technique, PSP provides the experimenter with a global distribution of pressure on a painted surface. To demonstrate frequency response and enhanced sensitivity to pressure changes, a PSP system consisting of a polymer∕ceramic matrix binder with platinum tetra(pentafluorophenyl) porphyrin (PtTFPP) as the oxygen probe was applied to a wall inside an acoustic resonance cavity excited at 1.3 kHz. A data acquisition technique based on the luminescent decay lifetime of the oxygen sensors excited by a single pulse of light afforded the ability to capture instantaneous pressure fields with no phase-averaging. Superimposed wave-like structures were observed with a wavelength corresponding to a 4.7% difference from the theoretical value for a sound wave emanating from the speaker. High sound pressure cases upwards of 145 dB (re 20 μPa) exhibited skewed nodal lines attributed to a nonlinear acoustic field. The lowest sound pressure level of 125.4 dB--corresponding to an amplitude of 52.7 Pa, or approximately 0.05% of standard sea-level atmospheric pressure--showed that the paint could resolve the spatial details of the mode shape at the given resonance condition.
authors.affiliation: Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43235, USA.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Disotell
authors.forename: James W
authors.initials: JW
authors.lastname: Gregory