Reduced Order Model for Unsteady Aerodynamics of Flapping Wing Micro Air Vehicle in Hover

This paper describes a methodology to predict the loads generated by a flexible flapping wing. The three-dimensional, whole field wing deformation was first measured using a non-contact optical technique. The measured deformation and motion were then input to a reduced-order model of the flapping wing to calculate the loads generated. Experiments were performed on a thin rectangular plate of 100 mm wing length flapping in air at a frequency of 15 Hz and stroke amplitude of 40°. The wing deformation as well as wing root loads were measured and showed good agreement with previously published data. A direct numerical simulation of the Navier–Stokes equation with exactly the same configuration, but at lower Reynolds number, provided full-field dataset for the development of data-driven reduced-order models. A modified proper orthogonal decomposition-Galerkin method, which includes extra terms to represent moving boundaries, was applied for reduced-order model development. It was found that the reduced-order model with only eight proper orthogonal decomposition modes was sufficient to show good correlation of loads with direct numerical simulations and experimentally measured trends.

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The Study of Aeroelastic Reduced-Order Model Based on CFD/CSD Method and its Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.978.131 ◽

2014 ◽

Vol 978 ◽

pp. 131-134

Author(s):

Rui Li ◽

Chang Hong Tang

Keyword(s):

Harmonic Balance ◽

Unsteady Aerodynamics ◽

Harmonic Balance Method ◽

Reduced Order Model ◽

Reduced Order Models ◽

Order Model ◽

Reduced Order ◽

Advantages And Disadvantages ◽

Aeroelastic Analysis ◽

Proper Orthogonal

Unsteady aerodynamics research is the foundation of aeroelastic analysis. How to effectively improve the aeroelastic computational efficiency,it is the key of current research on aeroelasticity now.Reduced order models are proposed as a powerful tool to solve this problem. Analyzed the three reduced-order models for Volterra ,Proper Orthogonal Decomposition and Harmonic Balance method ,their advantages and disadvantages were pointed out. The direction of the reduced order model in the future was Proposed and some suggest was given out for its application.

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Support-Vector-Machine-Based Reduced-Order Model for Limit Cycle Oscillation Prediction of Nonlinear Aeroelastic System

Mathematical Problems in Engineering ◽

10.1155/2012/152123 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 13

Author(s):

Gang Chen ◽

Yingtao Zuo ◽

Jian Sun ◽

Yueming Li

Keyword(s):

Support Vector Machine ◽

Limit Cycle ◽

Unsteady Aerodynamics ◽

Reduced Order Model ◽

Support Vector ◽

Limit Cycle Oscillation ◽

Order Model ◽

Aeroelastic System ◽

Reduced Order ◽

Cycle Oscillation

It is not easy for the system identification-based reduced-order model (ROM) and even eigenmode based reduced-order model to predict the limit cycle oscillation generated by the nonlinear unsteady aerodynamics. Most of these traditional ROMs are sensitive to the flow parameter variation. In order to deal with this problem, a support vector machine- (SVM-) based ROM was investigated and the general construction framework was proposed. The two-DOF aeroelastic system for the NACA 64A010 airfoil in transonic flow was then demonstrated for the new SVM-based ROM. The simulation results show that the new ROM can capture the LCO behavior of the nonlinear aeroelastic system with good accuracy and high efficiency. The robustness and computational efficiency of the SVM-based ROM would provide a promising tool for real-time flight simulation including nonlinear aeroelastic effects.

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Time-Dependent Coefficient Reduced-Order Model for Unsteady Aerodynamics of Proprotors

Journal of Aircraft ◽

10.2514/1.4817 ◽

2005 ◽

Vol 42 (1) ◽

pp. 138-147 ◽

Cited By ~ 12

Author(s):

M. Gennaretti ◽

L. Greco

Keyword(s):

Unsteady Aerodynamics ◽

Reduced Order Model ◽

Time Dependent ◽

Order Model ◽

Reduced Order

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A Hybrid Reduced-Order Model for the Aeroelastic Analysis of Flexible Subsonic Wings—A Parametric Assessment

Aerospace ◽

10.3390/aerospace5030076 ◽

2018 ◽

Vol 5 (3) ◽

pp. 76 ◽

Cited By ~ 3

Author(s):

Marco Berci ◽

Rauno Cavallaro

Keyword(s):

Structural Parameters ◽

Equations Of Motion ◽

Three Dimensional ◽

Unsteady Aerodynamics ◽

Reduced Order Model ◽

Order Model ◽

Flexible Wings ◽

Reduced Order ◽

Aeroelastic Analysis ◽

Strip Theory

A hybrid reduced-order model for the aeroelastic analysis of flexible subsonic wings with arbitrary planform is presented within a generalised quasi-analytical formulation, where a slender beam is considered as the linear structural dynamics model. A modified strip theory is proposed for modelling the unsteady aerodynamics of the wing in incompressible flow, where thin aerofoil theory is corrected by a higher-fidelity model in order to account for three-dimensional effects on both distribution and deficiency of the sectional air load. Given a unit angle of attack, approximate expressions for the lift decay and build-up are then adopted within a linear framework, where the two effects are separately calculated and later combined. Finally, a modal approach is employed to write the generalised equations of motion in state-space form. Numerical results were obtained and critically discussed for the aeroelastic stability analysis of a uniform rectangular wing, with respect to the relevant aerodynamic and structural parameters. The proposed hybrid model provides sound theoretical insights and is well suited as an efficient parametric reduced-order aeroelastic tool for the preliminary multidisciplinary design and optimisation of flexible wings in the subsonic regime.

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Aerodynamic Simulation and Analysis for Biomimetic Flapping-Wing Robot

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.29-32.1301 ◽

2010 ◽

Vol 29-32 ◽

pp. 1301-1306

Author(s):

Jin Xu ◽

Liang Chen ◽

Wei Sun

Keyword(s):

Aerodynamic Force ◽

Unsteady Aerodynamics ◽

Flapping Wing ◽

Micro Air Vehicle ◽

Geometric Similarity ◽

Aerodynamic Model ◽

Air Vehicle ◽

Flight Parameters ◽

Rotary Wing ◽

Aerodynamic Simulation

As a new conceptual micro air vehicle, biomimetic flapping-wing robots have the advantages of small sizes, light weights, high maneuverability, and perfect aerodynamic performance. Flapping-wing robot can produce more effective aerodynamic force than traditional fixed-wing or rotary-wing aircrafts. Unsteady aerodynamics at low Reynolds number is the main theory applied to micro air vehicle analysis. In this paper, the flight parameters for a flapping-wing robot are designed with geometric similarity firstly. Then an improved aerodynamic model with optimized parameters is established. Lastly, some simulation and analysis are presented to illustrate and verify the feasibility and effectiveness of the models.

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Eigenmode Analysis in Unsteady Aerodynamics: Reduced Order Models

Applied Mechanics Reviews ◽

10.1115/1.3101718 ◽

1997 ◽

Vol 50 (6) ◽

pp. 371-386 ◽

Cited By ~ 73

Author(s):

Earl H. Dowell ◽

Kenneth C. Hall ◽

Michael C. Romanowski

Keyword(s):

Unsteady Flow ◽

Unsteady Aerodynamics ◽

Reduced Order Modeling ◽

Reduced Order Model ◽

Full Potential ◽

Order Model ◽

Reduced Order ◽

Unsteady Aerodynamic ◽

Eigenmode Analysis ◽

Wide Range

In this article, we review the status of reduced order modeling of unsteady aerodynamic systems. Reduced order modeling is a conceptually novel and computationally efficient technique for computing unsteady flow about isolated airfoils, wings, and turbomachinery cascades. Starting with either a time domain or frequency domain computational fluid dynamics (CFD) analysis of unsteady aerodynamic or aeroacoustic flows, a large, sparse eigenvalue problem is solved using the Lanczos algorithm. Then, using just a few of the resulting eigenmodes, a Reduced Order Model of the unsteady flow is constructed. With this model, one can rapidly and accurately predict the unsteady aerodynamic response of the system over a wide range of reduced frequencies. Moreover, the eigenmode information provides important insights into the physics of unsteady flows. Finally, the method is particularly well suited for use in the active control of aeroelastic and aeroacoustic phenomena as well as in standard aeroelastic analysis for flutter or gust response. Numerical results presented include: 1) comparison of the reduced order model to classical unsteady incompressible aerodynamic theory, 2) reduced order calculations of compressible unsteady aerodynamics based on the full potential equation, 3) reduced order calculations of unsteady flow about an isolated airfoil based on the Euler equations, and 4) reduced order calculations of unsteady viscous flows associated with cascade stall flutter, 5) flutter analysis using the Reduced Order Model. This review article includes 25 references.

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