Year: 2022
Type: article
Abstract: Modal analysis of fluid flows is essential for understanding flow physics and fluid–solid interaction mechanisms and for implementing flow control. Unlike unstable flows, the intrinsic stability of subcritical flows has led to failures in experimentally extracting the clear structure of the subcritical flow modes. To this end, this paper proposes an experimental modal testing method for subcritical flows. Using dynamic mode decomposition, dominant modes of flow around a cylinder at subcritical Reynolds numbers are extracted experimentally for the first time. The extracted structure and parameters of the modes are in agreement with the numerical results in the literature. It is found that the first-order mode is the stable von Kármán mode and can be observed at a Reynolds number as low as 19.3, which is nearly identical to the lower boundary of subcritical vortex-induced vibration. This finding provides the first experimental evidence of the correlation between the von Kármán mode and fluid–solid interaction instability in subcritical flows.
Source: Physics of Fluids
DOI: 10.1063/5.0101624
Authors: Zhen Lyu, Jiaqing Kou, Weiwei Zhang
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4281888102