Journal ArticleDOI
Flow physics and dynamics of flow-induced pitch oscillations of an airfoil
Karthik Menon,Rajat Mittal +1 more
TLDR
In this article, a sharp-interface immersed boundary method is used to simulate two-dimensional incompressible flow, and this is coupled with the equations for a rigid foil supported at the elastic axis with a linear torsional spring.Abstract:
We conduct a computational study of flow-induced pitch oscillations of a rigid airfoil at a chord-based Reynolds number of 1000. A sharp-interface immersed boundary method is used to simulate two-dimensional incompressible flow, and this is coupled with the equations for a rigid foil supported at the elastic axis with a linear torsional spring. We explore the effect of spring stiffness, equilibrium angle-of-attack and elastic-axis location on the onset of flutter, and the analysis of the simulation data provides insights into the time scales and mechanisms that drive the onset and dynamics of flutter. The dynamics of this configuration includes complex phenomena such as bifurcations, non-monotonic saturation amplitudes, hysteresis and non-stationary limit-cycle oscillations. We show the utility of ‘maps’ of energy exchange between the flow and the airfoil system, as a way to understand, and even predict, this complex behaviour.read more
Citations
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Journal ArticleDOI
Airfoil-like mechanics generate thrust on the anterior body of swimming fishes
TL;DR: High-resolution, pressure-based approach is applied to describe how two fishes, bluegill sunfish and brook trout, swimming in the carangiform mode, generate thrust on their anterior bodies using leading-edge suction mechanics, much like an airfoil, which are suggested to be highly efficient and used by a wide range of fishes.
Journal ArticleDOI
Effect of dielectric barrier discharge plasma actuator on the dynamic moment behavior of pitching airfoil at low Reynolds number
Journal ArticleDOI
On the initiation and sustenance of flow-induced vibration of cylinders: insights from force partitioning
Karthik Menon,Rajat Mittal +1 more
TL;DR: In this article, the physical mechanisms that drive and sustain flow-induced, transverse vibrations of cylinders are dissected by using a method to partition the fluid dynamic force on the cylinder into distinct, physically relevant components.
Journal ArticleDOI
Dynamic mode decomposition based analysis of flow over a sinusoidally pitching airfoil
Karthik Menon,Rajat Mittal +1 more
TL;DR: In this article, the authors present a method for decomposing the flow on or near a moving boundary by a change of reference frame, followed by a correction to the computed modes that is determined by the frequency spectrum of the motion.
Journal ArticleDOI
Nonlinear flow-induced instability of an elastically mounted pitching wing
TL;DR: In this article, the structural parameters of an elastically mounted pitching wing were simulated and regulated using a cyber-physical control system, and the authors observed that the system dynamics bifurcates from stable fixed points to small-amplitude oscillations followed by large-amptitude limit-cycle oscillations via a subcritical bifurbation, which features hysteretic bistability and an abrupt amplitude jump.
References
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Book
Nonlinear dynamics and Chaos
TL;DR: The logistic map, a canonical one-dimensional system exhibiting surprisingly complex and aperiodic behavior, is modeled as a function of its chaotic parameter, and the progression through period-doubling bifurcations to the onset of chaos is considered.
Journal ArticleDOI
Immersed boundary methods
Rajat Mittal,Gianluca Iaccarino +1 more
TL;DR: The term immersed boundary (IB) method is used to encompass all such methods that simulate viscous flows with immersed (or embedded) boundaries on grids that do not conform to the shape of these boundaries.
Journal ArticleDOI
Nonlinear Dynamics and Chaos: With Applications to Physics, Biology, Chemistry and Engineering
TL;DR: This book discusses Chaos, Fractals, and Dynamics, and the Importance of Being Nonlinear in a Dynamical View of the World, which aims to clarify the role of Chaos in the world the authors live in.
General Theory of Aerodynamic Instability and the Mechanism of Flutter
TL;DR: In this paper, the Kutta condition was used to analyze the aerodynamic forces on an oscillating airfoil or an air-foil-aileron combination of three independent degrees of freedom.
Journal ArticleDOI
Vortex-induced vibrations
TL;DR: In this paper, a review summarizes fundamental results and discoveries concerning vortex-induced vibration (VIV) that have been made over the last two decades, many of which are related to the push to explore very low mass and damping, and to new computational and experimental techniques that were hitherto not available.
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A sharp-interface immersed boundary method with improved mass conservation and reduced spurious pressure oscillations
Jung Hee Seo,Rajat Mittal +1 more