Nonlinear fluid damping of elastically mounted pitching wings in quiescent water

TL;DR

This study experimentally investigates the nonlinear fluid damping of a rigid, elastically mounted pitching wing in still water, revealing a universal scaling law and analyzing flow fields to understand damping behavior.

Contribution

It introduces a universal fluid damping scaling law for elastically mounted wings and analyzes flow fields to explain nonlinear damping behaviors.

Findings

Proposes a universal fluid damping scaling law.

Analyzes flow fields to explain nonlinear damping.

Measures damping coefficients across various parameters.

Abstract

We experimentally study the nonlinear fluid damping of a rigid but elastically mounted pitching wing in the absence of a freestream flow. The dynamics of the elastic mount are simulated using a cyber-physical system. We perturb the wing and measure the fluid damping coefficient from damped oscillations over a large range of pitching frequencies, pitching amplitudes, pivot locations and sweep angles. A universal fluid damping scaling is proposed to incorporate all these parameters. Flow fields obtained using particle image velocimetry are analyzed to explain the nonlinear behaviors of the fluid damping.