Nonlinear Modeling of Unsteady Aerodynamics at High Angle of Attack

2004 ◽  
Author(s):  
Daniel Allwine ◽  
Jeremy Strahler ◽  
Douglas Lawrence ◽  
Jerry Jenkins ◽  
James Myatt
Keyword(s):  
Nonlinear Modeling ◽  
Angle Of Attack ◽  
Unsteady Aerodynamics ◽  
High Angle ◽  
High Angle Of Attack

Research on Unsteady Aerodynamics Modeling Based on Back Propagation Algorithm at High Angle of Attack

2013 ◽  
Vol 392 ◽  
pp. 170-177 ◽  
Author(s):  
Hong Biao Wang ◽  
Bin Bin Lv ◽  
Xiao Juan Yang ◽  
Tai Yuan Luo
Keyword(s):  
Neural Network ◽  
Network Model ◽  
Neural Network Model ◽  
Bp Neural Network ◽  
Angle Of Attack ◽  
Unsteady Aerodynamics ◽  
Test Results ◽  
High Angle ◽  
High Angle Of Attack ◽  
Bp Neural Network Model

with the BP algorithm, this paper sets up the High angle of attack unsteady aerodynamic neural network model. By using the large-amplitude pitch oscillation dynamic test data of some slender model in high-speed wind tunnel, this paper trains and verifies the BP neural network model and discusses elements which may influence the arithmetic speed and prediction accuracy of the neural network model. Test results show that the established BP neural network model matches the wind tunnel test results nicely and has relatively good capacity to predict the High angle of attack unsteady aerodynamics.

scholarly journals Leading Edge Blowing to Mimic and Enhance the Serration Effects for Aerofoil

2021 ◽  
Vol 11 (6) ◽  
pp. 2593
Author(s):  
Yasir Al-Okbi ◽  
Tze Pei Chong ◽  
Oksana Stalnov
Keyword(s):  
Boundary Layer ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Boundary Layer Separation ◽  
Shear Instability ◽  
Vortical Flow ◽  
High Angle ◽  
High Angle Of Attack ◽  
Layer Separation ◽  
Aerodynamic Performances

Leading edge serration is now a well-established and effective passive control device for the reduction of turbulence–leading edge interaction noise, and for the suppression of boundary layer separation at high angle of attack. It is envisaged that leading edge blowing could produce the same mechanisms as those produced by a serrated leading edge to enhance the aeroacoustics and aerodynamic performances of aerofoil. Aeroacoustically, injection of mass airflow from the leading edge (against the incoming turbulent flow) can be an effective mechanism to decrease the turbulence intensity, and/or alter the stagnation point. According to classical theory on the aerofoil leading edge noise, there is a potential for the leading edge blowing to reduce the level of turbulence–leading edge interaction noise radiation. Aerodynamically, after the mixing between the injected air and the incoming flow, a shear instability is likely to be triggered owing to the different flow directions. The resulting vortical flow will then propagate along the main flow direction across the aerofoil surface. These vortical flows generated indirectly owing to the leading edge blowing could also be effective to mitigate boundary layer separation at high angle of attack. The objectives of this paper are to validate these hypotheses, and combine the serration and blowing together on the leading edge to harvest further improvement on the aeroacoustics and aerodynamic performances. Results presented in this paper strongly indicate that leading edge blowing, which is an active flow control method, can indeed mimic and even enhance the bio-inspired leading edge serration effectively.

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