Impulsive force measurement by fast response pressure-sensitive paint during shock wave passage

Abstract The interaction between a shock wave and an object causes an impulsive force on the object that lasts for a very short time on the order of milliseconds. This study proposes impulsive force measurements using anodized aluminum pressure-sensitive paint (AA-PSP), which is an optical pressure measurement technique. The response time of AA-PSP is on the order of microseconds, indicating the potential for fast pressure drag measurements by integrating the pressure distribution on the surface. In this study, at first, the response time of the fabricated AA-PSP is measured and determined to be $$3.3~\upmu \hbox {s}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>3.3</mml:mn> <mml:mspace/> <mml:mi>μ</mml:mi> <mml:mtext>s</mml:mtext> </mml:mrow> </mml:math> . A cylindrical model coated with the AA-PSP is installed at the outlet of a shock tube, and the surface pressure is measured in order to calculate the pressure drag with a time resolution of $$10~\upmu \hbox {s}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>10</mml:mn> <mml:mspace/> <mml:mi>μ</mml:mi> <mml:mtext>s</mml:mtext> </mml:mrow> </mml:math> . The experimental results are compared with an Euler CFD simulation computed using an in-house code. The maximum pressure drag in the numerical result exceeds that in the experimental result; however, the maximum pressure drag timings are in good quantitative agreement. In addition to measuring the impulsive force, the AA-PSP results allow for the visualization of complex flow phenomena, such as diffraction and decay in the shock wave strength. This simultaneous measurement of the flow field and impulsive forces can deepen the understanding of the relationship between them.