TY - JOUR
T1 - Feather-inspired flow control device across flight regimes
AU - Othman, Ahmed K.
AU - Nair, Nirmal J.
AU - Goza, Andres
AU - Wissa, Aimy
N1 - The authors would like to acknowledge funding from the National Science Foundation (Award No. 2029028). Moreover, certain images in this publication have been obtained by the author(s) from the Pixabay website, where they were made available under the Pixabay License. To the extent that the law allows, IOP Publishing disclaims any liability that any person may suffer as a result of accessing, using, or forwarding the image(s). Any reuse rights should be checked and permission should be asked for, if necessary, from Pixabay and/or the copyright owner (as appropriate) before using or forwarding the image(s).
The authors would like to acknowledge funding from the National Science Foundation (Award No. 2029028). Moreover, certain images in this publication have been obtained by the author(s) from the Pixabay website, where they were made available under the Pixabay License. To the extent that the law allows, IOP Publishing disclaims any liability that any person may suffer as a result of accessing, using, or forwarding the image(s). Any reuse rights should be checked and permission should be asked for, if necessary, from Pixabay and/or the copyright owner (as appropriate) before using or forwarding the image(s).
PY - 2023/11/1
Y1 - 2023/11/1
N2 - Bio-inspired flow control strategies can provide a new paradigm of efficiency and adaptability to overcome the operational limitations of traditional flow control. This is particularly useful to small-scale uncrewed aerial vehicles since their mission requirements are rapidly expanding, but they are still limited in terms of agility and adaptability when compared to their biological counterparts, birds. One of the flow control strategies that birds implement is the deployment of covert feathers. In this study, we investigate the performance characteristics and flow physics of torsionally hinged covert-inspired flaps mounted on the suction side of a NACA2414 airfoil across different Reynolds numbers, specifically 200,000 and 1,000. These two Reynolds numbers are representative of different avian flight regimes where covert feathers have been observed to deploy during flight, namely cruising and landing/perching. We performed experiments and simulations where we varied the flap location, the hinge stiffness, and the moment of inertia of the flap to investigate the aerodynamic performance and describe the effects of the structural parameters of the flap on the aerodynamic lift improvements. Results of the study show up to 12% lift improvement post-stall for the flapped cases when compared to the flap-less baseline. The post-stall lift improvement is sensitive to the flap’s structural properties and location. For instance, the hinge stiffness controls the mean deflection angle of the flap, which governs the resulting time-averaged lift improvements. The flap moment of inertia, on the other hand, controls the flap dynamics, which in turn controls the flap’s lift-enhancing mechanism and how the flap affects the instantaneous lift. By examining the time-averaged and instantaneous lift measurement, we uncover the mechanisms by which the covert-inspired flap improves lift and highlights similarities and differences across Reynolds numbers. This article highlights the feasibility of using covert-inspired flaps as flow control across different flight missions and speeds.
AB - Bio-inspired flow control strategies can provide a new paradigm of efficiency and adaptability to overcome the operational limitations of traditional flow control. This is particularly useful to small-scale uncrewed aerial vehicles since their mission requirements are rapidly expanding, but they are still limited in terms of agility and adaptability when compared to their biological counterparts, birds. One of the flow control strategies that birds implement is the deployment of covert feathers. In this study, we investigate the performance characteristics and flow physics of torsionally hinged covert-inspired flaps mounted on the suction side of a NACA2414 airfoil across different Reynolds numbers, specifically 200,000 and 1,000. These two Reynolds numbers are representative of different avian flight regimes where covert feathers have been observed to deploy during flight, namely cruising and landing/perching. We performed experiments and simulations where we varied the flap location, the hinge stiffness, and the moment of inertia of the flap to investigate the aerodynamic performance and describe the effects of the structural parameters of the flap on the aerodynamic lift improvements. Results of the study show up to 12% lift improvement post-stall for the flapped cases when compared to the flap-less baseline. The post-stall lift improvement is sensitive to the flap’s structural properties and location. For instance, the hinge stiffness controls the mean deflection angle of the flap, which governs the resulting time-averaged lift improvements. The flap moment of inertia, on the other hand, controls the flap dynamics, which in turn controls the flap’s lift-enhancing mechanism and how the flap affects the instantaneous lift. By examining the time-averaged and instantaneous lift measurement, we uncover the mechanisms by which the covert-inspired flap improves lift and highlights similarities and differences across Reynolds numbers. This article highlights the feasibility of using covert-inspired flaps as flow control across different flight missions and speeds.
KW - avian-inspired flight
KW - bio-inspired flow control
KW - feather-inspired device
KW - fluid-structure interaction
UR - http://www.scopus.com/inward/record.url?scp=85173558159&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85173558159&partnerID=8YFLogxK
U2 - 10.1088/1748-3190/acfa4f
DO - 10.1088/1748-3190/acfa4f
M3 - Article
C2 - 37714167
AN - SCOPUS:85173558159
SN - 1748-3182
VL - 18
JO - Bioinspiration and Biomimetics
JF - Bioinspiration and Biomimetics
IS - 6
M1 - 066010
ER -