Experimental investigation on flow structures of steadily translating low-aspect-ratio wings in low Reynolds number flow

In recent decades, Micro Air Vehicles (MAVs) have been a hot topic for their promising future. But the promotions of MAVs are hindered by short endurances. To solve this problem, inspirations brought from migratory butterflies who utilize ‘flapping-gliding’ skill during long-distance migration to improve flight efficiency. The butterfly’s gliding flights, which can be simplified considering steadily translating fixed wings, drawn high attentions. Previous studies mainly focus on aerodynamics low-aspect-ratio wings at Re ≈ 105 via force measurements. However, few experimental measured 3D flow fields. Consequently, underlying lift-to-drag ratio mechanisms in butterfly-shaped still not clear. shed new light structures around were captured and investigated detail.