Three-Dimensional Computational Fluid Flow Analysis of Bio-inspired Corrugated wing at Low Reynolds Number.

A computational study was performed to analyze the airflow over bio-inspired corrugated wings. The bio-inspired corrugated wing profiles were derived from the mid-span section of the forewing of Aeshna Cyanea dragonfly species. Additionally, a hybrid non-corrugated profile was also created possessing geometric similarities with the corrugated airfoils to compare and visualize the effects of corrugation on the fluid flow. The computational analysis was conducted for 4,8-, and 12-degrees angles of attack. Streamlines obtained from the computational analysis results (carried out on ANSYS CFX) showed the formation of secondary flows or vortices that are trapped in the valleys of the corrugated wings which was not observed in the hybrid airfoil. This study also compares the effects of corrugation geometry on fluid flow behavior. It was also seen that the intensity and quantity of the secondary flows increased with the increase in the angle of attack.

Aerodynamic study of the corrugated airfoil at ultra-low Reynolds number

In this study, Aeshna cyanea dragonfly forewing mid-cross-section corrugated airfoil was simulated at ultra-low Reynolds number. The corrugated airfoil was compared with its smooth counterpart to study the effect of the corrugations upon the aerodynamic performance. Unsteady two-dimensional laminar flow was solved using FLUENT. This study was divided into gliding phase and flapping phase. In the gliding phase, the corrugated airfoil produced a higher lift force with respect to the profiled airfoil at both tested Reynolds numbers ([Formula: see text], [Formula: see text]) with comparable drag coefficient for all the tested angles of attack. In the flapping phase, both the corrugated airfoil and the flat-plate have a very similar flow behavior which yields a very similar aerodynamic performance at Re[Formula: see text]. A structural analysis was performed to compare the corrugated airfoil with the flat-plate. The analysis revealed the superiority of the corrugated airfoil over the flat-plate in decreasing the deflection under the applied load. The reduced frequency was varied to study its impact on the aerodynamic performance. By increasing the reduced frequency, the thrust and the lift forces increased by [Formula: see text]% and [Formula: see text]%, respectively. Any increase in the reduced frequency will increase lift and thrust forces, but the propulsive efficiency will deteriorate.

Checklist of the dragonflies (Odonata) of Iran with new records and notes on distribution and taxonomy

Iran has a complex dragonfly fauna influenced by contacts and overlaps of different geographical zones. Its fauna is dominated by Eurosiberian taxa. However, the SE Province Sistãn-va-Baluchestãn is rich in oriental species, many of which having their western distribution limit in Iran. In NE-Iran, Irano-Turanian elements live and in the S- and SW-Iran African species are found. The Iranian Odonata fauna seems well studied, however, a closer look reveals many uncertainties and confusion, some records coming clearly from misidentification whereas other, which were missing proofs of correct identification remains to be confirmed. Even today, every new collecting trip reveals species new for Iran whereas species new for science are still detected, although rarely. In this checklist we include seven taxa new for Iran: Stylurus ubadschii (although a male of uncertain origin is recorded in Schmidt (1954), Ischnura senegalensis (although two uncertain records were published by Martin (1912) and Schmidt (1954), Coenagrion ponticum, C. lunulatum, C. pulchellum, Lestes macrostigma, and Calopteryx splendens tschaldirica. We critically checked all available data, including all published records. Fourteen taxa have been rejected, or placed in the category for need of confirmation. Till the end of 2017, 100 autochthonous taxa of dragonflies and two migratory species could be confirmed to be or have been present in Iran. We provide distribution maps, created after evaluation of published data and containing our own data from 12 trips to Iran, travelling over 35000 km in the country. Over 200 new localities are integrated. Taxonomic confusion is reduced by rejecting the following taxa for Iran: Calopteryx splendens mingrelica, C. hyalina, Erythromma najas, Aeshna cyanea, Gomphus davidi, and Sympetrum sinaiticum. We regard the taxa Gomphus amseli and G. schneiderii transcaspicus as synonyms of G. schneiderii, and Onychogomphus forcipatus lucidostriatus as a synonym of O. f. albotibialis.