The present study investigates the complex vortex interactions in two-dimensional flow-field behind a symmetric NACA0012 airfoil undergoing prescribed periodic pitching-plunging motion low Reynolds number regime. transitions from to chaotic through quasi-periodic route as plunge amplitude is gradually increased. This unravels role of that take place among main structures making unsteady transition periodicity chaos. leading-edge separation plays key providing very first trigger for...

This study investigates the transitional wake dynamics of a simultaneously pitching– heaving airfoil in low Reynolds number regime. The transition from Kármán to reverse wakes and subsequent deflection are known take place entirely periodic regime as dynamic heave velocity $\kappa h$ (proportionally, amplitude-based Strouhal $St_A$ ) is gradually increased. However, further increase may result loss stability deflected vortex street an eventual chaos. phenomenon has largely remained...

This paper numerically investigates the influence of a fixed downstream control cylinder on flow-induced vibration an elastically supported primary cylinder. These two cylinders are situated in tandem arrangement with small dimensionless center-to-center spacing (L/D, L is intermediate and D diameter). The present two-dimensional (2D) simulations carried out low Reynolds number (Re) regime. focus this study to reveal underlying flow physics behind transition from vortex-induced galloping...

This study investigates energy harvesting from vortex induced vibrations of a flexible cantilevered flapper placed in the wake rigid circular cylinder. The effect gap between cylinder and on harvested is investigated through wind tunnel experiments numerical simulations. As flow speed varied, transition dynamics observed, which turn affects power extracted by harvester. Numerical investigations reveal that different depending whether vortices are shed ahead or behind flapper. concludes...

The effect of a chordwise flexible aft-tail rigid heaving aerofoil on the dynamical transitions trailing-wake is studied here. two-way coupled fluid–solid dynamics simulated using an in-house fluid–structure interaction (FSI) platform, comprising discrete forcing immersed boundary method based incompressible Navier–Stokes solver, weakly with finite difference structural solver. FSI in comparison to corresponding tail configuration. For latter, mild jet-switching due quasi-periodic movement...

Abstract This paper investigates the effect of permeability on two-dimensional rectangular plates at incidences. The flow topology is investigated for Reynolds number ( Re ) values between 30 and 90, forces plate are discussed $$Re=30$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mi>e</mml:mi> <mml:mo>=</mml:mo> <mml:mn>30</mml:mn> </mml:mrow> </mml:math> , where wake found to be steady any value Darcy Da incidence $$\alpha $$...

This study focuses on characterizing the bifurcation scenario and underlying synchrony behavior in a nonlinear aeroelastic system under deterministic as well stochastic inflow conditions. Wind tunnel experiments are carried out for canonical pitch-plunge subjected to dynamic stall The is observed undergo subcritical Hopf bifurcation, giving way large-amplitude limit cycle oscillations (LCOs) flutter regime flow At this condition, we observe intermittent phase synchronization between pitch...

Abstract Ambient energy harvesting from the vortex-induced vibration (VIV) of circular cylinders has been extensively studied in recent years. However, effect multiple splitters attached to cylinder surface different configurations on performance is not well understood date. This study focused enhancing piezoelectric flow-induced a by using two symmetric relative angular positions with respect oncoming uniform flow. Both wind tunnel experiments and numerical simulations are carried out seven...

The effects of a rigid barrier on the stability structure while it is undergoing phase-locked motions due to surrounding fluid–structure interactions, are studied. primary and near wake dynamics modeled as harmonic oscillator Van der Pol oscillator, respectively, weakly coupled via acceleration coupling. Qualitative changes in dynamical behavior this system investigated context discontinuity-induced bifurcations that result from interaction fluid flow nonsmoothness impact structure....

The present paper investigates the flow induced dynamics of a non-linear fluid-structure interaction (FSI) system comprising symmetrical NACA 0012 airfoil supported by springs. Two methods are used in calculating aerodynamic loads: linear analytical approach and full Navier-Stokes (N-S) solution. is based on assumption potential theory rigid wake. Wind velocity as bifurcation parameter shows that structural response undergoes supercritical Hopf bifurcation. However, loads predict unrealistic...

The present study focuses on identifying dynamical transition boundaries and presents an order-to-chaos map for the unsteady flow field of a flapping foil in low Reynolds number regime. effect extensive parametric space, covering large kinematic conditions, has been investigated. It is shown that conventional non-dimensional parameters cannot effectively capture changes due to variations relevant are unable demarcate boundaries. Two new measures – maximum effective angle attack leading-edge...

The effects of sweep angle and reduced frequency on the leading-edge vortex (LEV) structure over flapping swept wings in Reynolds number (Re) range O(104) are yet to be completely understood. With increasing interest designing bio-inspired micro-air-vehicles, understanding LEV dynamics such scenarios is imperative. This study investigates three different angles (Λ=0°, 30°, 60°) through high-fidelity improved delayed detached eddy simulation analyze underlying flow physics. Plunge ramp...

The effect of stochastic inflow fluctuations on the jet-switching characteristics a harmonically plunging elliptic foil at low Reynolds number regime has been analyzed in present study. are generated by simulating an Ornstein–Uhlenbeck process—a stationary Gauss–Markov process—with chosen correlation function. In absence fluctuations, quasi-periodic movement wake vortices plays key role bringing out κh ≥ 1.5. However, fluctuating alters organized arrangement vortex street even lower (κh =...

Abstract An algorithm to generate universal matrices for plane triangular finite elements the general ‘quasi‐harmonic’ equation is presented. For every member of triangle family three numerical are obtained which independent size, shape and ‘material’ properties element. Of these, two basic third can be generated from one these two. The element ‘stiffness’ matrix conveniently by manipulating taking into account material in a simple manner.

View Video Presentation: https://doi.org/10.2514/6.2022-4138.vid An integral boundary-layer formulation is used to dynamically detect the occurrence of detachment if any, and its location on airfoil surface. Weak separation or 'boundary-layer thickening' modeled through viscous-inviscid interaction between flow outer flow. The appearance a singularity in solution signals detachment, which should then be release discrete vortices. A criterion indicator Csep , introduced this research,...