This study experimentally investigates aerodynamic characteristics and flow fields of a smooth owl-like airfoil without serrations and velvet structures. This biologically inspired airfoil design is intended to serve as the main-wing for low-Reynolds-number aircrafts such as micro air vehicles. Reynolds number dependency on aerodynamics is also evaluated at low Reynolds numbers. The results of the study show that the owl-like airfoil has high lift performance with a nonlinear lift increase due to the presence of a separation bubble on the suction side. A distinctive flow feature of the owl airfoil is a separation bubble on the pressure side at low angles of attack. The separation bubble switches location from the pressure side to the suction side as the angle of attack increases and is continuously present on the surface within a wide range of angles of attack. The Reynolds number dependency on the lift curves is insignificant, although differences in the drag curves are especially pronounced at high angles of attack. Eventually, we obtain the geometric feature of the owl-like airfoil to increase aerodynamic performance at low Reynolds numbers.
Falls of elderly during walking cause serious injury as fracture probably. Most of falls results from tripping, Minimum Toe Clearance(MinTC) indicating easiness to tripping was studied by a lot of researchers. It was reported that variability of MinTC was greater in the elderly than the young. This paper proposes a method to make a judgement on easiness to tripping based on the height of MinTC using One Dimensional Brightness Distribution Sensor. For the purpose, we detected the difference between normal gait and dangerous gait using our method. As a result, our method obtained the significant difference between normal and dangerous gait. In conclusion, we clearly judged normal gait or dangerous gait using our proposal system. In the future, we should test at the actual environment, develop further.
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