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

2005 ◽  
Vol 42 (1) ◽  
pp. 138-147 ◽  
Author(s):  
M. Gennaretti ◽  
L. Greco
Keyword(s):  
Unsteady Aerodynamics ◽  
Reduced Order Model ◽  
Time Dependent ◽  
Order Model ◽  
Reduced Order

A Reduced Order Model for Multi-Group Time-Dependent Parametrized Reactor Spatial Kinetics

2014 ◽  
Author(s):  
Alberto Sartori ◽  
Davide Baroli ◽  
Antonio Cammi ◽  
Lelio Luzzi ◽  
Gianluigi Rozza
Keyword(s):  
Reduced Order Model ◽  
Time Dependent ◽  
Element Approximation ◽  
Fissile Material ◽  
Spatial Effects ◽  
Reduced Basis ◽  
Order Model ◽  
Control Rod ◽  
Reduced Order ◽  
Group Time

In this work, a Reduced Order Model (ROM) for multi-group time-dependent parametrized reactor spatial kinetics is presented. The Reduced Basis method (built upon a high-fidelity “truth” finite element approximation) has been applied to model the neutronics behavior of a parametrized system composed by a control rod surrounded by fissile material. The neutron kinetics has been described by means of a parametrized multi-group diffusion equation where the height of the control rod (i.e., how much the rod is inserted) plays the role of the varying parameter. In order to model a continuous movement of the rod, a piecewise affine transformation based on subdomain division has been implemented. The proposed ROM is capable to efficiently reproduce the neutron flux distribution allowing to take into account the spatial effects induced by the movement of the control rod with a computational speed-up of 30000 times, with respect to the “truth” model.

Linear Reduced-Order Model for Unsteady Aerodynamics of an L-Shaped Gurney Flap

2015 ◽  
Vol 52 (6) ◽  
pp. 1887-1904 ◽  
Author(s):  
Valentina Motta ◽  
Giuseppe Quaranta
Keyword(s):  
Unsteady Aerodynamics ◽  
Reduced Order Model ◽  
Order Model ◽  
Reduced Order ◽  
Gurney Flap

In-Plane Stretching in MEMS Actuated Deformable Mirrors

2006 ◽  
Author(s):  
Vineel Mallela ◽  
John Zhe ◽  
D. Dane Quinn
Keyword(s):  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Reduced Order Model ◽  
Time Dependent ◽  
Deformable Mirror ◽  
Discrete Elements ◽  
Order Model ◽  
Reduced Order ◽  
Mems Actuators ◽  
Geometrically Exact Shell

We consider the response of a continuously deformable mirror with discrete MEMS actuators. The mirror itself is described with a geometrically exact shell model incorporating both flexural and extensional strains, while the MEMS actuators are represented as discrete elements subject to a time-dependent voltage. A reduced-order model is developed through a Galerkin reduction and the resulting equations are subjected to the method of multiple scales. The response of the system is then analyzed to uncover the ability of the system follow desired mirror profiles.

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

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.

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

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
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.

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

Aerospace ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 76 ◽  
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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