Pitch Rate Induced Separation Delay Modeling of Dynamic Stall and Stall Flutter

2019 ◽  
Author(s):  
Ethan C. Culler ◽  
John A. Farnsworth
Keyword(s):  
Dynamic Stall ◽  
Stall Flutter

scholarly journals Stall Flutter Control of a Smart Blade Section Undergoing Asymmetric Limit Oscillations

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Nailu Li ◽  
Mark J. Balas ◽  
Pourya Nikoueeyan ◽  
Hua Yang ◽  
Jonathan W. Naughton
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Control Algorithm ◽  
Dynamic Stall ◽  
Helicopter Rotor ◽  
Sensor Signal ◽  
Helicopter Rotor Blade ◽  
Blade Section ◽  
Control Capability ◽  
Stall Flutter

Stall flutter is an aeroelastic phenomenon resulting in unwanted oscillatory loads on the blade, such as wind turbine blade, helicopter rotor blade, and other flexible wing blades. Although the stall flutter and related aeroelastic control have been studied theoretically and experimentally, microtab control of asymmetric limit cycle oscillations (LCOs) in stall flutter cases has not been generally investigated. This paper presents an aeroservoelastic model to study the microtab control of the blade section undergoing moderate stall flutter and deep stall flutter separately. The effects of different dynamic stall conditions and the consequent asymmetric LCOs for both stall cases are simulated and analyzed. Then, for the design of the stall flutter controller, the potential sensor signal for the stall flutter, the microtab control capability of the stall flutter, and the control algorithm for the stall flutter are studied. The improvement and the superiority of the proposed adaptive stall flutter controller are shown by comparison with a simple stall flutter controller.

Dynamic Stall of an Airfoil With Leading Edge Bubble Separation Involving Time Dependent Re-Attachment

1978 ◽  
Author(s):  
H. Tokel ◽  
F. Sisto
Keyword(s):  
Leading Edge ◽  
Physical Problem ◽  
Dynamic Stall ◽  
Time Dependent ◽  
Harmonic Oscillations ◽  
Bubble Separation ◽  
Periodic Growth ◽  
Stall Flutter ◽  
The Mathematical Model ◽  
Dependent Point

The dynamic stall of an airfoil with leading edge bubble separation is analyzed. The stall flutter of turbomachine blading may involve periodic growth and collapse of such a bubble. The mathematical model representing the physical problem is presented. A flat plate undergoing harmonic oscillations with time-dependent point of re-attachment is studied for the perturbed aerodynamic reactions and applications to the stall flutter problem.

Stall Induced Vibration and Flutter in a Symmetric Airfoil

2006 ◽  
Author(s):  
Sunetra Sarkar ◽  
Hester Bijl
Keyword(s):  
Initial Conditions ◽  
Dynamical Behavior ◽  
Turbine Rotor ◽  
Dynamic Stall ◽  
Aeroelastic Stability ◽  
Aeroelastic Analysis ◽  
Structural Nonlinearity ◽  
Stall Flutter ◽  
The Stability ◽  
Wind Turbine Rotor

In this paper the aeroelastic stability of a wind turbine rotor in the dynamic stall regime is investigated. Two dimensional stall flutter models have been chosen for the aeroelastic stability analysis. Two different aeroelastic models have been considered. First, a pitching oscillation, and second, a flap-edgewise oscillation of an airfoil. Previous nonlinear aeroelastic analysis on such systems are not exhaustive. Parameters like structural non-linearity and initial conditions have not been studied, while these have a significant influence on the overall dynamics. They have now been taken up in the present analysis. The overall study helps towards a better understanding of the stall flutter mechanism in such aeroelastic systems. The study has found a strong influence of structural nonlinearity on the bifurcation pattern. Initial condition, too, plays an important role on the stability behavior as well as on the bifurcation pattern. Other system parameters of influence are nondimensional airspeed and external forcing. Interesting dynamical behavior like period-three and also super-harmonic and quasi-harmonic response have been found in the forced system, not reported before.

Numerical study of dynamic stall on several airfoil sections

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 128-130
Author(s):  
Emmanuel Guilmineau ◽  
Patrick Queutey
Keyword(s):  
Numerical Study ◽  
Dynamic Stall
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