圆角方形断面气动特性试验

通过刚性测压模型风洞试验,在均匀流场中测试了圆角率R/D=0.4的方形断面在0°～45°风向角、雷诺数Re=0.8×10~5～3.8×10~5时的气动特性。结果表明:试验雷诺数范围内,所有风向角下模型的阻力系数均值、升力系数均值、升力系数脉动值及斯特罗哈数基本上都受到雷诺数的影响。与其他风向角相比,0°～17.5°风向角时,阻力系数均值和升力系数均值受雷诺数的影响更大; 7.5°～45°风向角时,升力系数脉动值受雷诺数的影响更大; 0°～12.5°风向角时,斯特罗哈数受雷诺数的影响更大。

Aerodynamic Characteristics of Square Prism with Rounded Corner

Aiming at feature evaluation and model optimization problem of remaining life prediction of rolling bearings,a method of feature evaluation and model optimization for bearing life is proposed. Based on the monotonicity and sensitivity evaluation of the bearing characteristics, this method quantitatively evaluates the bearing capacity tracking ability, and then selects the multidimensional feature sets that characterize the degradation of bearing performance. In order to reduce the influence of the redundant information between the multidimensional feature sets on the life prediction, multidimensional feature sets are clustered and filtered by using the Affinity propagation (AP) clustering method. In order to describe the characterization of the bearing degradation state uniformly after AP clustering, self-organizing feature map (SOM) is used to construct the bearing health index. Finally, the dual exponential model is optimized by adaptive chaos particle swarm optimization (ACPSO) to predict the remaining bearing life. The test shows that the method can accurately describe the bearing operating period and effectively predict the bearing remaining life.