Experiments on vortex shedding from flat plates with square leading and trailing edges

Abstract

Vortex shedding from flat plates with square leading and trailing edges having chord-to-thickness ratios 3–16 at Reynolds numbers (1–3) × 103 is investigated experimentally in low-speed wind tunnels. It is shown that vortex shedding from flat plates with square leading and trailing edges is characterized by the impinging-shear-layer instability where the separated shear layer becomes unstable in the presence of a sharp trailing edge corner. The Strouhal number which is based on the plate's chord is approximately constant and equal to 0.6 for chord-to-thickness ratios 3–5. With further increase in the ratio it increases stepwise to values that are approximately equal to integral multiples of 0.6.

Fluid–structure interaction-induced oscillation of flexible structures in laminar and turbulent flows

“…This influence was studied for example, by Nakamura, Ohya & Tsuruta (1991) (Re = 1000), Knisely (1990) (720 Re 31 000) and Parker & Welsh (1983) (17 000 Re 35 000).…”

Flow-induced vibration of elastically supported rectangular cylinders

“…Furthermore, the modified Strouhal numbers established for stationary rectangular cylinders and based on the length of the cylinder (Nakamura et al, 1991) do not predict the critical reduced velocity where vibrations first occur. However, the modified Strouhal numbers based on the aspect ratio (Naudascher and Wang, 1993;Matsumoto, 1999) accurately predict the critical reduced velocity where lock-in occurs.…”

“…This has been termed trailing edge vortex shedding. The velocity of the von Kârmân vortex street is approximately 86% of the free-stream velocity (Nakamura, et al, 1991).…”

“…However, the velocity of the reattached fluid is only approximately 63% that of the free-stream velocity (Nakamura, et al, 1991). The reattached fluid is stable and forms a laminar flow that is shed from the trailing edge of the body.…”

“…Knisely (1990) (Knisely, 1990). (Nakamura, et al, 1991). excitation to occur, the alternating pressure loading must occur principally on the after-body surface.…”