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Simulation of flapping wings subjected to gusty inflow
Published in Cambridge University Press
2019
Volume: 123
   
Issue: 1266
Pages: 1170 - 1192
Abstract
Ornithopters and entomopters should be insensitive to the gusty environment during outdoor operations. Hence, it becomes imperative to understand their behaviour under the influence of gust for ensuring stable flight. In light of this, the present numerical study focused on understanding the aerodynamics of flapping wings with five different planform shapes under the influence of a spatiotemporally varying frontal gust. 3D, unsteady, laminar, and incompressible Navier-Stokes equations were solved using finite volume formulation. A canonical case of asymmetric 1 degree of freedom (DoF) flapping kinematics was considered. Horizontal and vertical force patterns in constant and gusty inflow conditions were numerically computed and compared. Findings were analyzed quantitatively by comparing the differences in the instantaneous force patterns, ordinal scoring approach, and phase space plots. Qualitative comparisons were made based on plots of vortex structures and surface pressure contours for constant and gusty inflow conditions for wings with different planform shapes. Spanwise Lagrangian Coherent Structures (LCS) of all the five wings were also compared. Studies revealed that the elliptical wing exhibited low sensitivity and inverse semi-elliptical wing exhibited high sensitivity to the gusty inflow. Rectangular, triangular and semi-elliptical shaped wings were moderately sensitive to the gusty inflow. This finding, within the limitations of the flapping kinematics and simulation conditions considered for the present study, supported the fact that many natural flyers like forest raptors, non-migratory passerines, pheasants, and partridges have adopted elliptical wing planform for efficient flight. © Royal Aeronautical Society 2019.
About the journal
JournalData powered by TypesetAeronautical Journal
PublisherData powered by TypesetCambridge University Press
ISSN00019240
Open AccessNo
Concepts (14)
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    Degrees of freedom (mechanics)
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    Flight simulators
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    KINEMATICS
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    Lagrange multipliers
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    Navier stokes equations
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    Phase space methods
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    Vortex flow
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    Wings
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    1 DOF ASYMMETRIC FLAPPING
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    FRONTAL GUST
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    Lagrangian coherent structures
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    Q-CRITERIA
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    WING PLANFORMS
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    PLANFORMS