Simulating aeroelastic response of a self-sustained oscillating rigid airfoil using a boundary oscillation method

2020 ◽  
Vol 234 (11) ◽  
pp. 1811-1824
Author(s):  
MS Araghizadeh ◽  
MH Djavareshkian ◽  
J Rezaeepazhand
Keyword(s):  
Center Of Mass ◽  
Aeroelastic Response ◽  
Naca0012 Airfoil ◽  
Aerodynamic Model ◽  
Flutter Boundary ◽  
Time Marching ◽  
Axis Position ◽  
Determine System ◽  
Marching Method ◽  
Oscillation Method

The present study presents a new nonlinear unsteady aerodynamic model to investigate the aeroelastic behavior of a self-sustained oscillating rigid airfoil. Here the unsteady Euler equations are considered simulating inviscid compressible transonic flow over an oscillating airfoil. In regard to providing boundedness criteria, a high-order technique based on a normalized variable diagram scheme has been presented. Since using dynamic mesh for simulating flow over a dynamic airfoil is too complex and requires many computational efforts, the current paper proposes a nonorthogonal and static mesh with oscillation of flow boundary. The results are compared with both well-validated numerical methods and experimental data. A time-marching method is employed to determine system responses. The predicted flutter boundary for NACA0012 airfoil at different free-stream Mach numbers is in fair agreement with direct flutter tools of the Hopf bifurcation points. Finally, the influences of the center of mass and elastic axis position on the system aeroelastic behavior are examined.

Analytical and Experimental Aeroelastic Wing Flutter Analysis and Suppression

2015 ◽  
Vol 15 (06) ◽  
pp. 1450084 ◽  
Author(s):  
Khalid A. Alsaif ◽  
Mosaad A. Foda ◽  
Hachimi Fellouah
Keyword(s):  
Nonlinear Models ◽  
Linear Quadratic Regulator ◽  
System Response ◽  
Linear Quadratic ◽  
Aeroelastic Response ◽  
Naca0012 Airfoil ◽  
Aerodynamic Model ◽  
Full State ◽  
Full State Feedback ◽  
And Control

Aeroelastic response and control of airfoil-flap wing exposed to unsteady aerodynamic loads is addressed. The aim is to suppress flutter and to maintain stability of the system. The analytical aerodynamic model is featuring plunging–pitching–flapping coupled motion. Both linear and nonlinear models are developed. Linear quadratic regulator theory is used to design a full state feedback controller in state-space. The control law is implemented through the flap torque to suppress flutter instability and enhance the aeroelastic response. The system response is investigated when it is flying beyond the flutter speed and the control is delayed by a few seconds. The effects of aircraft propeller excitation and the variation of the aspect ratio on the intitiation of flutter are investigated. Numerical simulations are complemented by experimental measurements in a wind tunnel for NACA0012 airfoil.

Ground Flutter Simulation Test Based on Reduced Order Modeling of Aerodynamics by CFD/CSD Coupling Method

2019 ◽  
Vol 11 (01) ◽  
pp. 1950008
Author(s):  
Binwen Wang ◽  
Xueling Fan
Keyword(s):  
Aerodynamic Force ◽  
Test System ◽  
Simulation Test ◽  
Robust Controller ◽  
Test Technique ◽  
Reduced Order ◽  
Aerodynamic Model ◽  
Flutter Boundary ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

Flutter is an aeroelastic phenomenon that may cause severe damage to aircraft. Traditional flutter evaluation methods have many disadvantages (e.g., complex, costly and time-consuming) which could be overcome by ground flutter test technique. In this study, an unsteady aerodynamic model is obtained using computational fluid dynamics (CFD) code according to the procedure of frequency domain aerodynamic calculation. Then, the genetic algorithm (GA) method is adopted to optimize interpolation points for both excitation and response. Furthermore, the minimum-state method is utilized for rational fitting so as to establish an aerodynamic model in time domain. The aerodynamic force is simulated through exciters and the precision of simulation is guaranteed by multi-input and multi-output robust controller. Finally, ground flutter simulation test system is employed to acquire the flutter boundary through response under a range of air speeds. A good agreement is observed for both velocity and frequency of flutter between the test and modeling results.

Calculation of the Quasi Three-Dimensional Flow in a Turbomachine Blade Row

1977 ◽  
Vol 99 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Jean-Pierre Veuillot
Keyword(s):  
Finite Difference ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Through Flow ◽  
Blade Row ◽  
Time Marching ◽  
Space Discretization ◽  
Finite Volume Approach ◽  
Marching Method ◽  
Finite Difference Techniques

The equations of the through flow are obtained by an asymptotic theory valid when the blade pitch is small. An iterative method determines the meridian stream function, the circulation, and the density. The various equations are discretized in an orthogonal mesh and solved by classical finite difference techniques. The calculation of the steady transonic blade-to-blade flow is achieved by a time marching method using the MacCormack scheme. The space discretization is obtained either by a finite difference approach or by a finite volume approach. Numerical applications are presented.

Effect of Segmented Electrodes on Piezo-Elastic and Piezo-Aero-Elastic Responses of Generator Plates

2009 ◽  
Author(s):  
Carlos De Marqui ◽  
Alper Erturk ◽  
Daniel J. Inman
Keyword(s):  
Electrical Power ◽  
Elastic Behavior ◽  
Elastic Model ◽  
Fe Model ◽  
Aeroelastic Response ◽  
Aerodynamic Model ◽  
Frequency Excitation ◽  
Elastic Responses ◽  
Electrical Power Output ◽  
Tip Mass

In this paper, the use of segmented electrodes is investigated to avoid cancellation of the electrical outputs of the torsional modes in energy harvesting from piezo-elastic and piezo-aero-elastic systems. The piezo-elastic behavior of a cantilevered plate with an asymmetric tip mass under base excitation is investigated using an electromechanically coupled finite element (FE) model. Electromechanical frequency response functions (FRFs) are obtained using the coupled FE model both for the continuous and segmented electrodes configurations. When segmented electrodes are considered torsional modes also become significant in the resulting electrical FRFs, improving broadband (or varying-frequency excitation) performance of the generator plate. The FE model is also combined with an unsteady aerodynamic model to obtain the piezo-aero-elastic model. The use of segmented electrodes to improve the electrical power generation from aeroelastic vibrations of plate-like wings is investigated. Although the main goal here is to obtain the maximum electrical power output for each airflow speed (both for the continuous and segmented electrode cases), piezoelectric shunt damping effect on the aeroelastic response of the generator wing is also investigated.

On the Use of Direct and Inverse Numerical Flow Calculations for Supersonic Turbine Design

1994 ◽  
Author(s):  
F. Pommel
Keyword(s):  
Flow Field ◽  
Euler Equations ◽  
Velocity Component ◽  
Normal Velocity ◽  
Blade Design ◽  
Blade Profile ◽  
Flow Solver ◽  
Time Marching ◽  
Turbine Design ◽  
Marching Method

A procedure for blade design, using a time marching method to solve the Euler equations in the blade-to-blade plane is presented. This procedure uses an Office Nationale d’Etude et de Recherches Aeronautique flow solver. The classical slip conditions (no normal velocity component along the blade profile) has been replaced by another boundary conditions in such a way that the required pressure may be imposed directly. The orignal direct code was therefore transformed into an inverse solver. The unknows are calculated on the blade wall using the so-called compatibility relations. The blade geometry is then modified by resetting the wall parallel to the new flow field. The results obtained with this design process for a supersonic turbine blade of a space turbopump is presented.

A Time Marching Method for Internal Flows Using Curvilinear Coordinates

1986 ◽  
Vol 10 (1) ◽  
pp. 8-15
Author(s):  
M. Reggio ◽  
R. Camarero
Keyword(s):  
Gas Dynamics ◽  
Curvilinear Coordinates ◽  
System Stability ◽  
Internal Flows ◽  
Axisymmetric Nozzle ◽  
Equations Of Gas Dynamics ◽  
Curvilinear Grid ◽  
Momentum Fluxes ◽  
Time Marching ◽  
Marching Method

A time-marching method for flows with nozzle and blade-to-blade applications is presented. The approach developed consists of solving the basic conservation equations of gas dynamics in conservation form on a curvilinear grid. The assumption of quasi-streamlines is satisfied by generating a body-fitted coordinate system. Stability is maintained by upwind differencing of the mass and momentum fluxes and downwind differencing of the pressure. The method is then applied to the solution of a plane and axisymmetric nozzle and to VKI’s gas turbine blade and compared to previous computations and experiments.

Sign in / Sign up

Export Citation Format

Share Document