A Lattice Boltzmann Framework for Analysis of 'Clap and Fling' Motion of Finite Thickness Membranes
24 Jun 2013-
TL;DR: In this paper, a two-dimensional numerical model for one and two-winged "clap and fling" stroke has been developed to study the aerodynamic performance of insect flight.
Abstract: In the past two decades, the lattice Boltzmann method (LBM) has offered itself as an alternative framework compared to the Navier Stokes simulations. However, the applicability of this method to simulate moving boundary problems has not received sufficient attention. The present study primarily focuses on developing and employing the halfway bounceback LBM to analyse the flow dynamics associated with the flapping motion of finite-thickness wings. A two-dimensional numerical model for one and two-winged ‘clap and fling’ stroke has been developed to study the aerodynamic performance of insect flight. The influence of kinematic parameters such as the percentage overlap between translational and rotational phase , the separation between two wings and different Reynolds numbers Re on lift generation has been studied and presented here. In addition, the time-dependent behaviour of the leading and trailing edge vortices and their role on lift generation in clap and fling type kinematics has been identified. Based on simulation data, regression analysis was carried out to express the mean lift coefficient as a function of the varied parameters. Results show that overlap ratio is the most influential parameter in enhancing lift. With increase in separation , the reduction in drag is far more dominant than the decrease in lift. With an increase in Re (which ranges between 8 and 128), the mean drag coefficient decreases monotonously, whereas the mean lift coefficient decreases to a minimum and increases thereafter. This behaviour of lift generation at higher Re was characterised by the ‘wing-wake interaction’ mechanism which was absent at low Re.
Citations
More filters
TL;DR: In this paper, the effects of flexibility, kinematic motions, and two-to-six-wing flapping configurations on the FMAV through numerical simulations were investigated, and it was shown that a rigid spanwise and flexible chordwise wing produces the highest lift with minimum power.
11 citations
16 Jun 2014
TL;DR: In this article, a twodimensional numerical model has been developed to probe the fluid mechanics associated with the vertical plunging motion of a flat plate analogous to the biological flight of birds and insects.
Abstract: The aim of the present study is to understand the mechanism of propulsion in biological flyers, initially starting from rest, towards development of micro-air vehicles employing the same concept using a computational analysis of the plunging motion of a rigid wing. A twodimensional numerical model has been developed to probe the fluid mechanics associated with the vertical plunging motion of a flat plate analogous to the biological flight of birds and insects. Recent experiments have shown that propulsion can be achieved in still air by a rigid wing if it is flapped above a critical Reynolds number (based on the flapping frequency). The influence of parameters such as density ratio ρ* and flapping Reynolds number Ref on the propulsion of a vertically heaving wing unconstrained to move in horizontal direction has been investigated. Flow fields generated at different time instants indicate that the interaction with the previous shed vortices creates asymmetry that pushes the wing into locomotion. The vortical wake patterns are scrutinized at steady translation which varied depending upon the Strouhal number. In addition, the behavior of input/output power and efficiency has been quantified.
3 citations
Cites methods from "A Lattice Boltzmann Framework for A..."
...The detailed description of the method, the force evaluation and boundary conditions employed is provided in an earlier publication [37]....
[...]
References
More filters
TL;DR: An overview of the lattice Boltzmann method, a parallel and efficient algorithm for simulating single-phase and multiphase fluid flows and for incorporating additional physical complexities, is presented.
Abstract: We present an overview of the lattice Boltzmann method (LBM), a parallel and efficient algorithm for simulating single-phase and multiphase fluid flows and for incorporating additional physical complexities. The LBM is especially useful for modeling complicated boundary conditions and multiphase interfaces. Recent extensions of this method are described, including simulations of fluid turbulence, suspension flows, and reaction diffusion systems.
6,565 citations
3,793 citations
TL;DR: In this paper, the authors show that the enhanced aerodynamic performance of insects results from an interaction of three distinct yet interactive mechanisms: delayed stall, rotational circulation, and wake capture.
Abstract: The enhanced aerodynamic performance of insects results from an interaction of three distinct yet interactive mechanisms: delayed stall, rotational circulation, and wake capture. Delayed stall functions during the translational portions of the stroke, when the wings sweep through the air with a large angle of attack. In contrast, rotational circulation and wake capture generate aerodynamic forces during stroke reversals, when the wings rapidly rotate and change direction. In addition to contributing to the lift required to keep an insect aloft, these two rotational mechanisms provide a potent means by which the animal can modulate the direction and magnitude of flight forces during steering maneuvers. A comprehensive theory incorporating both translational and rotational mechanisms may explain the diverse patterns of wing motion displayed by different species of insects.
2,246 citations
08 Mar 2001
TL;DR: A comprehensive theory incorporating both translational and rotational mechanisms may explain the diverse patterns of wing motion displayed by different species of insects.
Abstract: The enhanced aerodynamic performance of insects results from an interaction of three distinct yet interactive mechanisms: delayed stall, rotational circulation, and wake capture. Delayed stall functions during the translational portions of the stroke, when the wings sweep through the air with a large angle of attack. In contrast, rotational circulation and wake capture generate aerodynamic forces during stroke reversals, when the wings rapidly rotate and change direction. In addition to contributing to the lift required to keep an insect aloft, these two rotational mechanisms provide a potent means by which the animal can modulate the direction and magnitude of flight forces during steering maneuvers. A comprehensive theory incorporating both translational and rotational mechanisms may explain the diverse patterns of wing motion displayed by different species of insects.
2,133 citations
TL;DR: In this article, a general technique for simulating solid-fluid suspensions is described, which combines Newtonian dynamics of the solid particles with a discretized Boltzmann equation for the fluid phase; the many-body hydrodynamic interactions are fully accounted for, both in the creeping flow regime and at higher Reynolds numbers.
Abstract: A new and very general technique for simulating solid–fluid suspensions is described; its most important feature is that the computational cost scales linearly with the number of particles. The method combines Newtonian dynamics of the solid particles with a discretized Boltzmann equation for the fluid phase; the many-body hydrodynamic interactions are fully accounted for, both in the creeping-flow regime and at higher Reynolds numbers. Brownian motion of the solid particles arises spontaneously from stochastic fluctuations in the fluid stress tensor, rather than from random forces or displacements applied directly to the particles. In this paper, the theoretical foundations of the technique are laid out, illustrated by simple analytical and numerical examples; in a companion paper (Part 2), extensive numerical tests of the method, for stationary flows, time-dependent flows, and finite-Reynolds-number flows, are reported.
2,073 citations