Fluid–Structure Interaction of a Membranous Hemisphere in Turbulent Flow: PIV Measurements of the Flow and DIC Measurements of the Structure

Abstract

The present study investigates the fluid-structure interaction (FSI) of a highly flexible membranous hemisphere immersed into a fully turbulent boundary layer flow. The experiments are carried out in a wind tunnel considering three Reynolds numbers (50,000, 75,000 and 100,000) defined by the diameter of the hemisphere and the free-stream velocity. A gauge pressure inside the hemisphere is used to stabilize the thin-walled structure against the outer wind loads. This setup is comparable to air-inflated structures often used in civil engineering. A combination of mono particle-image-velocimetry (PIV) measurements for the fluid field and three-dimensional digital-image correlation (DIC) measurements for the structure deformation are used to evaluate the occurring FSI phenomena. Additionally, a constant-temperature hot-wire probe is applied at specific locations in the flow field in order to link the independently gathered PIV and DIC data. Furthermore, all measurements are compared with the results of a rigid hemisphere leading to a characterization of the FSI between the turbulent flow field and the flexible structure. Besides the analysis and investigation of the occurring FSI phenomena, the measurements build the basis for validating complementary numerical high-fidelity simulations of the coupled problem.