Development of a PVDF Piezo-Film Sensor for Unsteady Wall-Pressure Measurements in SBLIs

Abstract

Abstract An innovative, flexible wall-pressure sensor array for unsteady flow conditions has been developed and evaluated in a turbulent shockwave-boundary layer interaction (SBLI) setup at Mach 2. Compared to the previous version, the new sensor’s flexibility makes it easier to fit on different surfaces, while offering enhanced durability and improved sensitivity. The array comprises 18 circular sensors, each with a diameter of $$3\,{\text {mm}}$$ 3 mm , fabricated using screen printing techniques from a thin piezoelectric PVDF film (thickness: $$110\,\upmu {\text {m}}$$ 110 μ m ). Remarkably, this sensor array achieves excellent spatial resolution while minimizing flow interference, all at a fraction of the cost associated with traditional dynamic pressure transducers.To validate its performance, the sensor array underwent dynamic calibration using a ball-drop impact test device. Subsequently, it was rigorously tested in a supersonic wind tunnel, demonstrating strong agreement with reference measurements obtained using a state-of-the-art Kulite pressure sensor. The resulting premultiplied power spectral density $$f\cdot PSD$$ f · P S D distributions align closely with findings reported in existing literature. Notably, the low-frequency unsteadiness region beneath the separation shock foot ( $$X^*=0$$ X ∗ = 0 ) exhibits a Strouhal range of $$St=0.03-0.05$$ S t = 0.03 - 0.05 .