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.

scholarly journals A Surrogate-Based Approach to Reduced-Order Dynamic Stall Modeling

2012 ◽  
Vol 57 (2) ◽  
pp. 1-9 ◽  
Author(s):  
Bryan Glaz ◽  
Li Liu ◽  
Peretz P. Friedmann ◽  
Jeremy Bain ◽  
Lakshmi N. Sankar
Keyword(s):  
Rotor Blade ◽  
Computational Cost ◽  
Dynamic Stall ◽  
Helicopter Rotor ◽  
High Fidelity ◽  
Time Varying ◽  
Reduced Order ◽  
Passive Design ◽  
Helicopter Rotor Blade ◽  
Rotary Wing

The surrogate-based recurrence framework (SBRF) approach to reduced-order dynamic stall modeling associated with pitching/plunging airfoils subject to fixed or time-varying freestream Mach numbers is described. The SBRF is shown to effectively mimic full-order two-dimensional computational fluid dynamics solutions for unsteady lift, moment, and drag, but at a fraction of the computational cost. In addition to accounting for realistic helicopter rotor blade dynamics, it is shown that the SBRF can model advancing rotor shock induced separation as well as retreating blade stall associated with excessive angles of attack. Therefore, the SBRF is ideally suited for a variety of rotary-wing aeroelasticity and active/passive design optimization studies that require high-fidelity aerodynamic response solutions with minimal computational expense.

H ∞ Control of Smart Structure Helicopter Rotor Blade

1991 ◽  
Author(s):  
R. Kashani ◽  
S. Melkote ◽  
A. Sorgenfrei
Keyword(s):  
Rotor Blade ◽  
Active Vibration Control ◽  
Region Of Interest ◽  
Smart Structure ◽  
Helicopter Rotor ◽  
Appreciable Amount ◽  
Modelling Uncertainty ◽  
Helicopter Rotor Blade ◽  
Active Vibration ◽  
Bending Modes

Abstract Active vibration control of helicopter rotor blade is studied. For the purpose of illustration, we have considered only flap wise vibration of a hingeless rotor blade, and modelled it, using finite element method, by 20 beam elements. The first 12 bending modes of the system are considered in the model. A H∞ controller is designed for the plant formulated as above. The result of the numerical simulation of the closed-loop system shows that the control introduces an appreciable amount of damping in the frequency region of interest. The consideration of the modelling uncertainty in the synthesis of the controller resulted in a design which is robust stable in presence of formulated model uncertainty.

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