Flow Structures Around a Flapping-Wing Micro Air Vehicle Performing a Clap-and-Peel Motion

Perçin, Mustafa
Remes, Bart
The vortical flow structures generated by the flapping wings of the DelFly II micro air vehicle in hovering flight configuration are investigated using particle image velocimetry. Synchronous force measurements are carried out to establish the relation between the unsteady forces and force generation mechanisms: particularly, the leading-edge vortex and the clap-and-peel motion. The formation of conical leading-edge vortices on both wings is revealed, which occurs rapidly at the start of the outstroke as a result of the wing-wing interaction. The leading-edge vortices of the outstroke interact with those of the instroke, which are shed and, by mutual induction, advect upstream as a vortex pair at the end of previous instroke. The leading-edge vortex pairs induce a strong inflow into the region formed between the upper and lower wings during the peeling phase, resulting in the formation of a low-pressure region. This, together with the leading-edge vortices and a momentum increase formed by the clap, accounts for the generation of relatively higher forces during the outstroke. The cycle-averaged forces are estimated with reasonable accuracy by means of a momentum-based approach using wake velocity information with an average error of 15%.


Flow Visualization in the Wake of the Flapping-Wing MAV ’DelFly II’ in Forward Flight
Perçin, Mustafa; van Oudheusden, Bas W.; Remes, Bart; Ruijsink, R; de Wagter, C (2012-06-25)
Time-resolved velocity field measurements in the wake of the flapping wings of the DelFly II Micro Aerial Vehicle (MAV) in forward flight configuration were obtained by Stereoscopic Particle Image Velocimetry (Stereo-PIV). The PIV measurements were performed at several spanwise planes in the wake of the flapping wings and at a high framing rate to allow a reconstruction of the temporal development of the three dimensional wake structures throughout the flapping cycle. The wake reconstruction was performed b...
Three-dimensional vortex wake structure of a flapping-wing micro aerial vehicle in forward flight configuration
Perçin, Mustafa; Eisma, H. E.; Remes, B. D. W. (2014-09-01)
This paper investigates the formation and evolution of the unsteady three-dimensional wake structures generated by the flapping wings of the DelFly II micro aerial vehicle in forward flight configuration. Time-resolved stereoscopic particle image velocimetry (Stereo-PIV) measurements were carried out at several spanwise-aligned planes in the wake, so as to allow a reconstruction of the temporal development of the wake of the flapping wings throughout the complete flapping cycle. Simultaneous thrust-force me...
Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control
Zharfa, Mohammadreza; Ozturk, Ilhan; Yavuz, Mehmet Metin (2016-03-01)
The flow structure over a 35 deg swept delta wing is characterized in a low-speed wind tunnel using techniques of laser-illuminated smoke visualization, laser Doppler anemometry, and surface-pressure measurements. The effects of Reynolds numbers and attack angles on the evaluation of flow patterns are addressed within the broad range of Reynolds number 10(4) < Re < 10(5) and attack angle 3 deg < alpha < 10 deg. In addition, the effect of steady blowing through the leading edges of the wing on flow structure...
Flow visualization around a flapping-wing micro air vehicle in free flight
Del Estal Herrero, Alejandro; Perçin, Mustafa; Karasek, Matej; Van Oudheusden, Bas W. (null; 2018-10-05)
Flow visualizations have been performed on a free flying flapping-wing Micro Air Vehicle (MAV), using a large-scale particle image velocimetry (PIV) approach. The PIV method involves the use of helium filled soap bubbles (HFSB) as tracer particles. HFSB scatter light with much higher intensity than regular seeding particles and comparable to that reflected off the flexible flapping wings. This enables flow field visualization to be achieved also close to the flapping wings, in contrast to previous PIV exper...
Vortex Formation and Force Generation Mechanisms of the DelFly II in Hovering Flight
Tenaglia, A; Perçin, Mustafa; Van Oudheusden, Bas W.; Deng, Shuanghou; Remes, Bart (2014-08-12)
This paper addresses the unsteady aerodynamic mechanisms in the hovering flight of the DelFly II flapping-wing Micro Aerial Vehicle (MAV). Stereoscopic Particle Image Velocimetry (Stereo-PIV) were carried out around the wings at a high framing rate. Thrust-force was measured to investigate the relation between the vortex dynamics and the aerodynamic force generation. The results reveal that the Leading-Edge-Vortex (LEV), as well as the high flexibility of the wings, have a major effect on thrust generation....
Citation Formats
M. Perçin and B. Remes, “Flow Structures Around a Flapping-Wing Micro Air Vehicle Performing a Clap-and-Peel Motion,” AIAA JOURNAL, pp. 1251–1264, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/48140.