Unsteady aerodynamics of a model bristled wing in rapid acceleration motion

2021 ◽  
Vol 33 (11) ◽  
pp. 111902
Author(s):  
Yu Kai Wu ◽  
Yan Peng Liu ◽  
Mao Sun
Keyword(s):  
Unsteady Aerodynamics

Disturbance observer–based neural flight control for aircraft with switched time-varying distributed delays

2021 ◽  
pp. 095441002199850
Author(s):  
Dawei Wu ◽  
Jun Zhou ◽  
Hui Ye
Keyword(s):  
Flight Control ◽  
Disturbance Observer ◽  
Distributed Delay ◽  
Unsteady Aerodynamics ◽  
Feedback System ◽  
Functional Method ◽  
System Control ◽  
Time Varying ◽  
Time Varying Delay ◽  
Feedback System Control

In this article, the high angle of attack (AOA) maneuver control problem is studied under multiple disturbances and uncertainties. For the first time, the switched distributed delay is constructed to characterize the unsteady aerodynamics. Based on neural networks (NNs) and hyperbolic tangent function, the disturbance observer technique is extended to the nonstrict-feedback system control. To handle the switching problem, time-delay problem, and nonstrict-feedback problem caused by switched distributed delay terms, the Lyapunov–Krasovskii (LK) functional method and a variable separation method are cleverly combined. The proposed LK function can relax the constraints on time-varying delay. Finally, a disturbance observer–based neural finite-time prescribed performance flight control law is developed to improve the flight performance at high AOA, and its effectiveness has been verified through rigorous theoretical analysis and simulation experiments.

The Unsteady Aerodynamics of a Finite Supersonic Cascade With Subsonic Axial Flow

1973 ◽  
Vol 40 (3) ◽  
pp. 667-671 ◽  
Author(s):  
J. M. Verdon
Keyword(s):  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Supersonic Stream ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Combined Use ◽  
Cascade Analysis ◽  
Infinite Array ◽  
Typical Configuration ◽  
Phase Angles

A method is presented for determining the unsteady flow field and the aerodynamic response which occurs when a finite oscillating cascade is placed in a supersonic stream, which has a subsonic velocity component normal to the cascade. Solutions are obtained through the combined use of closed-form and numerical procedures. Computed results indicate that the finite cascade analysis should provide a reasonable indication of the influence of the cascade parameters on the response of the infinite array. A brief parametric study for a typical configuration reveals possible aerodynamic instabilities when the blades perform single-degree-of-freedom pitching oscillations over a broad range of frequencies and interblade phase angles.

scholarly journals Unsteady aerodynamics simulation for the road vehicle in combined roll and yaw motion

2016 ◽  
Vol 82 (835) ◽  
pp. 15-00675-15-00675 ◽  
Author(s):  
Jun IKEDA ◽  
Makoto TSUBOKURA ◽  
Yusuke NAKAE
Keyword(s):  
Unsteady Aerodynamics ◽  
Road Vehicle ◽  
The Road

Prediction of Wind Turbine Rotor Loads Using the Beddoes-Leishman Model for Dynamic Stall

1995 ◽  
Vol 117 (3) ◽  
pp. 200-204 ◽  
Author(s):  
K. Pierce ◽  
A. C. Hansen
Keyword(s):  
Wind Turbines ◽  
Aerodynamic Force ◽  
Unsteady Aerodynamics ◽  
Turbine Rotor ◽  
Dynamic Stall ◽  
University Of Utah ◽  
Horizontal Axis Wind Turbines ◽  
Wind Tunnel Data ◽  
The University ◽  
Wind Turbine Rotor

The Beddoes-Leishman model for unsteady aerodynamics and dynamic stall has recently been implemented in YawDyn, a rotor analysis code developed at the University of Utah for the study of yaw loads and motions of horizontal axis wind turbines. This paper presents results obtained from validation efforts for the Beddoes model. Comparisons of predicted aerodynamic force coefficients with wind tunnel data and data from the combined experiment rotor are presented. Also, yaw motion comparisons with the combined experiment rotor are presented. In general the comparisons with the measured data are good, indicating that the model is appropriate for the conditions encountered by wind turbines.

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