Force moment partitioning and scaling analysis of vortices shed by a 2D pitching wing in quiescent fluid
arXiv:2301.13373 · doi:10.1007/s00348-023-03698-5
Abstract
We experimentally study the dynamics and strength of vortices shed from a NACA 0012 wing undergoing sinusoidal pitching in quiescent water. We characterize the temporal evolution of the vortex trajectory and circulation over a range of pitching frequencies, amplitudes and pivot locations. By employing a physics-based force and moment partitioning method (FMPM), we estimate the vortex-induced aerodynamic moment from the velocity fields measured using particle image velocimetry. The vortex circulation, formation time and vorticity-induced moment are shown to follow scaling laws based on the feeding shear-layer velocity. The vortex dynamics, together with the spatial distribution of the vorticity-induced moment, provide quantitative explanations for the nonlinear behaviors observed in the fluid damping (Zhu et al., J. Fluid Mech., vol. 923, 2021, R2). The FMPM-estimated moment and damping are shown to match well in trend with direct force measurements, despite a discrepancy in magnitude. Our results demonstrate the powerful capability of the FMPM in dissecting experimental flow field data and providing valuable insights into the underlying flow physics.
21 pages, 11 figures
References in corpus (7)
- Flow over an espresso cup: Inferring 3D velocity and pressure fields from tomographic background oriented schlieren videos via physics-informed neural networks
- Uncovering near-wall blood flow from sparse data with physics-informed neural networks
- On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number
- Significance of the strain-dominated region around a vortex on induced aerodynamic loads
- Contribution of spanwise and cross-span vortices to the lift generation of low-aspect-ratio wings: Insights from force partitioning
- Nonlinear fluid damping of elastically mounted pitching wings in quiescent water
- Discrete shedding of secondary vortices along a modified Kaden spiral