The effects of flexibility and sweep angle on flow around cropped delta wing

To investigate the flow mechanism of micro-air-vehicle's layout, hydrogen bubble visualization on a series of models with different flexibility and sweep angle whose ratio of span to chord length is 0.5 was carried out in water tunnel.As the results shown,the rule of flow structure to obey at low Reynolds number is listed as follows: the flow around flexible wing follows the rule which is "Ω vortex-one pair of leading vortex-one pair of leading vortex and dual vortex-one pair of leading vortex,dual-vortex and tri-vortex-one pair of leading vortex and dual-vortex-one pair of leading vortex" as the sweep angle increases,the flow structures over rigid wing are almost the same as flexible one but without tri-vortex structure.