Open-jet facility for bio-inspired micro-air-vehicle flight experiment at low speed and high turbulence intensity

作     者：Zhifeng Liu Yue Yang 

作者机构：State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking University HEDPS-CAPT Peking University 

出 版 物：《Advances in Aerodynamics》 (空气动力学进展(英文))

年 卷 期：2024年第3期

页      面：93-111页

学科分类：080103[工学-流体力学] 08[工学] 080104[工学-工程力学] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported in part by the National Natural Science Foundation of China (Grant Nos. 11925201 and 11988102) the National Key R&D Program of China (Grant No. 2020YFE0204200) the Xplorer Prize 

摘      要：Bio-inspired micro-air-vehicles(MAVs) usually operate in the atmospheric boundary layer at a low Reynolds number and complex wind conditions including large-scale turbulence, strong shear, and gusts. We develop an open jet facility(OJF) to meet the requirements of MAV flight experiments at very low speed and high turbulence intensity. Powered by a stage-driven fan, the OJF is capable of generating wind speeds covering 0.1 – 16.8 m/s, with a velocity ratio of 100:1. The contraction section of the OJF is designed using an adjoint-driven optimization method, resulting in a contraction ratio of 3:1 and a length-to-diameter ratio of 0.75. A modularized design of the jet nozzle can produce laminar or high-turbulence wind conditions. Flow field calibration results demonstrate that the OJF is capable of producing a high-quality baseline flow with steady airspeed as low as 0.1 m/s, uniform region around 80% of the cross-sectional test area, and turbulence intensity around 0.5%. Equipped with an optimized active grid(AG), the OJF can reproduce controllable, fully-developed turbulent wind conditions with the turbulence intensity up to 24%, energy spectrum satisfying the five-thirds power law, and the uniform region close to 70% of the crosssectional area of the test section. The turbulence intensity, integral length scale, Kolmogorov length scale, and mean energy dissipation rate of the generated flow can be adjusted by varying the area of the triangular through-hole in the wings of the AG.