Chandan Bose

University of Birmingham · Aerospace Engineering (School of Metallurgy and Materials)

This study focuses on discerning the role of structural parameters on the bifurcation characteristics and the underlying synchronization mechanism in an aeroelastic system undergoing nonlinear stall behaviour. To that end, wind tunnel experiments are performed on a NACA 0012 airfoil capable of undergoing bending (plunging) and torsional (pitching)...

This paper numerically investigates the influence of a fixed downstream control cylinder on the flow-induced vibration of an elastically supported primary cylinder. These two cylinders are situated in a tandem arrangement with small dimensionless center-to-center spacing (L/D, L is the intermediate spacing and D is the cylinder diameter). The prese...

Vortex recapture underpins the exceptional mobility of nature’s finest fliers and swimmers. Utilized by agile fruit flies and efficient jellyfish, this phenomenon is well-documented in bulk fluids. Despite extensive studies on the neuston—a vital fluidic interface where diverse life forms interact between air and water—neuston vortical hydrodynamic...

The effects of sweep angle and reduced frequency on the leading-edge vortex (LEV) structure over flapping swept wings in the Reynolds number (Re) range of O(104) are yet to be completely understood. With increasing interest in designing bio-inspired micro-air-vehicles, understanding LEV dynamics in such scenarios is imperative. This study investiga...

The effects of sweep angle and reduced frequency on the leading-edge vortex (LEV) structure over flapping swept wings in the Reynolds number ($Re$) range of $\mathbf{O}(10^4)$ are yet to be completely understood. With increasing interest in designing bio-inspired micro-air-vehicles (MAVs), understanding LEV dynamics in such scenarios is imperative....

This paper numerically investigates the influence of a fixed downstream control cylinder on the flow-induced vibration of an elastically-supported primary cylinder. These two cylinders are situated in a tandem arrangement with small dimensionless centre-to-centre spacing (L/D, L is the intermediate spacing, and D is the cylinder diameter). The pres...

Effects of chord-wise flexibility as an instrument to control chaotic transitions in the wake of a flexible flapping foil have been studied here using an immersed boundary method-based in-house fluid-structure-interaction solver. The ability of the flapping foil at an optimum level of flexibility to inhibit chaotic transition, otherwise encountered...

The kinematics of a free-falling body in an incompressible homogeneous quiescent flow depends on at least two dimensionless groups such as, for example, the nondimensional mass M ≡ m / ρ L2 and the Galilei number Ga ≡ (m g / ρ)1/2 / ν , where m and L are the mass and length of the body, ρ and ν are the density and the kinematic viscosity of the flu...

The study investigates the wake dynamics of two actively pitching and passively heaving elliptic foils in a tandem configuration in the low Reynolds number regime. The numerical simulations are carried out using an inhouse fluid-structure interaction solver based on the Cut-Finite Element Method (CutFEM) on hierarchical b-spline grids. In this stud...

We numerically investigate the three-dimensional (3D) flow-field around porous disks at different incidence angles (α). In the previous research carried out by our group, Cum-mins et al.[1] revealed that a steady Separated Vortex Ring (SVR) forms in the wake of the highly porous pappus of dandelion seeds, which significantly enhances their flight e...

Swept wings are significant in many aerospace engineering applications, from micro-aerial vehicles to passenger aircraft design. The leading-edge vortex (LEV) is the key unsteady flow feature that underpins the enhanced lift generation, especially in flapping flight. The LEV dynamics of swept wings have been extensively studied in past to understan...

The flexible feathers of bird wings can significantly enhance aerodynamic characteristics through their passive deformation, especially in gusty environments. In this study, we conduct a numerical investigation to study the effects of the flexible flaps inspired by the covert of bird wings on the aerodynamic characteristics of fixed wings at an inc...

The present study focuses on identifying the dynamical transition boundaries and presents an order-to-chaos map for the unsteady flow-field past a flapping wing in the low Reynolds number regime. Such transitions are primarily dictated by the leading-edge vortex (LEV) growth and its transportation. Several kinematic and flow parameters can directly...

We undertake numerical simulations of three-dimensional (3D) porous disks at different incidence angles. Cummins et al. [1] were the first to show that the pappus of dandelion seeds adopts a highly porous wing to form a separated vortex ring to remain afloat, which can greatly enhance their flight capability and improve efficiency. This finding has...

This study investigates the bifurcation behaviour of wake-induced vibro-impacting systems considering fluid-structure interaction (FSI). The primary structure and the near wake dynamics are modelled as a harmonic oscillator a Van der Pol oscillator, respectively, and are weakly coupled to each other. A non-deformable barrier obstructing the motion...

This study investigates the bifurcation behaviour of wake-induced vibro-impacting systems considering fluid-structure interaction (FSI). The primary structure and the near wake dynamics are modelled as a harmonic oscillator a Van der Pol oscillator, respectively, and are weakly coupled to each other. A non-deformable barrier obstructing the motion...

This paper investigates the effect of discrete transverse gusts on the flight dynamics and descent velocity of two-dimensional free-falling permeable plates. Two-way coupled fluid-structure interaction simulations are carried out using an overset meshing strategy for a range of Galilei number (Ga) from 10 and 50, and of the nondimensional mass (m)...

This paper describes the flow past two-dimensional porous plates at a Reynolds number ($Re$) of 30 and for a range of Darcy number ($Da$) and flow incidence ($\alpha$) values. For a plate normal to the stream and vanishing $Da$, the wake shows a vortex dipole with negligible separation from the plate. With increasing $Da$, the separation between th...

Studies on the dispersal of plant seeds have recently revealed new fluid mechanics features that aid diaspores to remain airborne and travel long distances. Diaspores are the biological compounds comprising the seed and other tissues dispersed with it. Understanding the aerodynamics underpinning their dispersal can inspire the design of novel unpow...

Appropriate selection of the chord-wise flexibility can directly benefit the efficient design of flapping-type micro aerial vehicles and automated underwater vehicles. To that end, this work investigates the effect of chord-wise flexibility on the wake dynamics of a flexible flapping foil in comparison to a rigid foil having the same chord length a...

This study investigates the suppression mechanism of instabilities induced by fluid-structure interactions (FSI) using passive vibration absorption devices, such as nonlinear energy sink (NES). The present FSI framework comprises a low-order phenomenological model, wherein the wake effect is modeled using the classical Van der Pol oscillator. The s...

This study focuses on characterizing the bifurcation scenario and the underlying synchrony behavior in a nonlinear aeroelastic system under deterministic as well as stochastic inflow conditions. Wind tunnel experiments are carried out for a canonical pitch-plunge aeroelastic system subjected to dynamic stall conditions. The system is observed to un...

The effect of a chordwise flexible aft-tail of a rigid heaving aerofoil on the dynamical transitions of the trailing-wake is studied here. The two-way coupled fluid-solid dynamics is simulated using an in-house fluid-structure interaction (FSI) platform, comprising a discrete forcing immersed boundary method based incompressible Navier–Stokes solve...

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 boundary-layer detachment if any, and its location on the airfoil surface. Weak separation or ‘boundary-layer thickening’ is modeled through viscous-inviscid interaction between the boundary-layer f...

The present study focuses on investigating the bifurcation characteristics of a pitch–plunge aeroelastic system possessing coupled non-smooth nonlinearities, both in structural and aerodynamic fronts. To this end, a freeplay nonlinearity is considered in the stiffness of the pitch degree-of-freedom. The effects of dynamic stall arising due to large...

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 the low Reynolds number regime. The effect of an extensive parametric space, covering a large number of kinematic conditions, has been investigated. It is shown that the conventional non-dimen...

This study focuses on characterising the bifurcation scenario and the underlying synchrony behaviour in a nonlinear aeroelastic system under deterministic as well as stochastic inflow conditions. Wind tunnel experiments are carried out for a canonical pitch-plunge aeroelastic system subjected to dynamic stall conditions. The system is observed to u...

This study focuses on characterizing the fatigue damage accumulated in nonlinear aeroelastic systems subjected to stochastic inflows through both numerical simulations and wind tunnel experiments. In the mathematical model, nonlinearities are assumed to exist either in the structure (via a cubic hardening nonlinearity in the pitch stiffness), or in...

The present study focuses on investigating the bifurcation characteristics of a pitch-plunge aeroelastic system possessing coupled non-smooth nonlinearities, both in structural and aerodynamic fronts. To this end, a freeplay nonlinearity is considered in the stiffness of the pitch degree-of-freedom (DoF). The effects of dynamic stall arising due to...

An elastically-supported bluff body structure experiences high-amplitude vortex-induced vibrations (VIV) due to the coupled fluid-structure interactions (FSI) in the presence of oncoming flow. This study investigates the suppression mechanism of these FSI-induced instabilities using a passive vibration absorption device-nonlinear energy sink (NES)....

The corresponding article can be read at https://doi.org/10.2514/6.2022-1969.

This paper investigates the underlying flow physics of static stall on a finite wing in the presence of bio-inspired leading-edge protuberances (LEPs) at a Reynolds number of 6×10^4. We present Unsteady Reynolds Average Navier-Stokes (URANS) flow simulations of the static stall behavior of a three-dimensional wing (spanning from wall to wall) with...

This study focuses on characterizing the fatigue damage accumulated in nonlinear aeroelastic systems subjected to stochastic inflows through both numerical simulations and wind tunnel experiments. In the mathematical model, nonlinearities are assumed to exist either in the structure (via a cubic hardening nonlinearity in the pitch stiffness), or in...

This study investigates the dynamical behaviour of the flapping filament subjected to a uniform inlet velocity at a low Reynolds number, considering the heaving amplitude as a bifurcation parameter. A discrete forcing immersed boundary method (IBM)-based in-house fluid-structure interaction (FSI) solver is used for the present simulations. The flap...

Dynamic stall is a subject of continued interest in the aerodynamics and aeroelasticity communities due to its broad range of engineering and biological applications, such as helicopter rotor blades, rapidly maneuvering flight, wind turbines, jet engine compressor blades, or flapping of insect wings. This study focuses on investigating the unsteady...

The primary motivation behind this study comes from the need for developing innovative engineering systems to harvest ambient wind energy from different classes of flow-induced vibrations. This study deals with the piezoelectric energy harvesting from the flow-induced vibration of a bluff-body with two symmetric splitters of varying lengths install...

Vortex-Induced Vibration (VIV) is often modelled as a two-way-coupled phenomenon wherein the structure and the wake behave as two interacting oscillators. In this chapter, we analyse the coupled interactions between these two oscillators from the purview of synchronization theory. To that end, a low-order wake oscillator model comprising of a class...

This chapter focuses on investigating the response characteristics of a coupled non-smooth nonlinear aeroelastic system subjected to randomly fluctuating inflow. The non-smoothness in the structure can be attributed to freeplay nonlinearity, and the aerodynamic loads are dictated by dynamic stall condition. Stochastic inflow gives rise to noise-ind...

This study reports that the choice of a seemingly appropriate linear algebra solver may fail to arrive at the accurate unsteady flow-field solution, leading to non-physical results. To that end, we take up a well-studied canonical problem of a periodically pitching airfoil in uniform free-stream condition. Simulations are performed in the low Reyno...

Water entry/exit and water impact are found in a broad range of applications, starting from the biological propulsion of a jumping fish to various offshore Engineering problems. Aquatic jumpers exhibit complicated dynamics in order to produce the required thrust during the transition from water to air due to the change in the medium density. On the...

The present study aims to investigate the synchronization characteristics of a pitch-plunge aeroelastic system subjected to coupled structural free-play and dynamic stall-induced aerodynamic nonlinearities. The semi-empirical Leishman-Beddoes (LB) aerodynamic model is used to capture the dynamic stall phenomena at large angles-of-attack (AoA). A bi...

Ambient energy harvesting from the vortex-induced vibration of circular cylinders has been extensively studied in recent years. However, the effect of multiple splitters attached to the cylinder surface in different configurations on the energy harvesting performance is not well understood to date. This study is focused on enhancing the piezoelectr...

This study is focused on investigating hybrid piezoelectric energy harvesting from the flow-induced vibration of a circular cylinder by using two symmetric splitters in different relative angular positions with respect to the oncoming uniform flow. Wind tunnel experiments and numerical simulations are carried out to study the effect of different an...

This paper investigates theBose, Chandan transitional flow dynamics behind a passively flapping airfoil supported by nonlinear springs in the presence of gusty inflow.Gupta, Sayan The fluid-structure interaction (FSI) framework is composed of an incompressible Navier-Stokes solver weakly coupled with a two degree-of-freedom (dof) nonlinear structur...

This study investigates the three-dimensional flow dynamics of a low-aspect-ratio flapping wing at a Reynolds number of 250. A discrete immersed boundary method is employed to solve the three-dimensional Navier-Stokes equation. Kinematic parameters, particularly the amplitude and frequency of the flapping motion, are found to have significant effec...

The present work explores the role of phase-difference on the transitional flow dynamics of a pitching-plunging foil. An extensive parameter space of plunge amplitude (h) and phase offset (ϕ) between pitch-plunge motions is considered keeping the pitch amplitude and non-dimensional flapping frequency constant (α=15o & k=4). Numerical simulations ar...

The present study attempts to capture the fluid-structure interaction dynamics of a chord-wise flexible flapping wing system using a limited mode structural model coupled with a high-fidelity Navier-Stokes solver. The wing is modeled as two elliptic rigid foils connected by a non-linear torsional spring that incorporates the chord-wise bending stif...

The present work focuses on investigating the underlying flow physics behind the transition from periodicity to aperiodicity in the flow past a harmonically plunging elliptic foil as the plunge amplitude is increased to a high value. Two-dimensional (2D) numerical simulations have been performed in the low Reynolds number regime using an in-house f...

The present paper aims to gain an understanding of the physics associated with the fluid-structure interaction behavior of a flexible filament interacting with the wake of an upstream rigid cylinder situated at a finite distance. The computational framework of the present high fidelity numerical simulations consist of an incompressible Navier-Stoke...

This study investigates the transitional wake dynamics of a simultaneously pitching-heaving airfoil in the low Reynolds number regime. The transition from K\'arm\'an to reverse K\'arm\'an wakes and the subsequent wake deflection are known to take place entirely in the periodic regime as the dynamic heave velocity $\kappa h$ (proportionally, the amp...

The effect of stochastic inflow fluctuations on the jet-switching characteristics of a harmonically plunging elliptic foil at a low Reynolds number regime has been analysed in the present study. The inflow fluctuations are generated by simulating an Ornstein-Uhlenbeck process - a stationary Gauss-Markov process - with a chosen correlation function....

Find the paper at: https://www.esi-group.com/sites/default/files/resource/other/1704/8th_OpenFOAM_Conference_IIT_Madras_Chatterjee.pdf

The present study focuses on formulating a fluid–structure interaction (FSI) framework by coupling a finite element analysis (FEA) based structural solver and a lumped vortex method (LVM) based potential flow solver to study the coupled dynamics involved in the undulatory and oscillatory swimming of fishes. The caudal fin of a carangiform fish is m...

The present paper numerically investigates the aerodynamic characteristics of a chord-wise flexible filament-like structure subjected to a fluctuating inflow in terms of the wake of a rigid cylinder situated upstream in the low Reynolds number regime (RED = 500, where D is the diameter of the cylinder). The numerical simulations are performed with...

The present work focuses on investigating the underlying flow physics behind the transition from periodicity to aperiodicity in the flow past a harmonically plunging elliptic foil as the plunge amplitude is increased to a high value. Two-dimensional (2D) numerical simulations have been performed in the low Reynolds number regime using an in-house f...

The present work is focused on investigating the effect of noisy input fluctuations on a harmonically plunging elliptic foil in the low Reynolds number regime (Re=300). Simulations are carried out using a discrete forcing Immersed Boundary Method (IBM) based in-house Navier-Stokes solver. The stochastic noisy inlet velocity is modeled as the Ornste...

Full text link: http://hdl.handle.net/10603/405340

This paper focuses on investigating the aerodynamic load generation of rigid and flexible wings undergoing asymmetric flapping motion through wind tunnel experiments in uniform inflow condition. The aerodynamic forces of the designed flapping wing setup are measured through a 6-dof force/torque sensor. A rigid wing and two different flexible membra...

This study focuses on numerically analyzing the transition from periodic to chaotic dynamics in the fluid-elastic response of a 2-dof flexibly-mounted airfoil with chord-wise rigidity. The computational framework is composed of a high fidelity Navier–Stokes solver, weakly coupled with a structural model having geometric nonlinearity represented by...

This study investigates the transitional flow dynamics in the wake of a pitching-plunging airfoil in the low Reynolds number regime. In the periodic regime, the transition from Karman to reverse Karman vortex-streets and the subsequent wake deflection with a gradual increase in the amplitude based Strouhal number (St) are well investigated in the l...

This study focuses on numerically analyzing the transition from periodic to chaotic dy- namics in the fluid-elastic response of a 2-dof spring-mounted airfoil, which models the behavior of a chord-wise rigid wing with span-wise flexibility. The computational framework is composed of a high fidelity Navier-Stokes solver, weakly coupled with a struct...

This study deals with energy harvesting from vortex-induced vibration (VIV) of a flexible cantilever plate placed in the wake of a rigid cylinder. Conventionally, the plate is designed to resonate with the vortex shedding frequency behind the cylinder at a given flow velocity. The experimental results presented here show that the frequency of the p...

The present paper is focused on understanding the fluid-structure interaction (FSI) behavior associated with the flow-induced vibrations of a chordwise flexible filament subjected to perturbed flows. The perturbed flow-field is generated in terms of the wake of a rigidly held cylinder situated upstream in the presence of a steady uniform free-strea...