scholarly journals The Use of Gramian Matrices for Aeroelastic Stability Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Douglas Domingues Bueno ◽  
Clayton Rodrigo Marqui ◽  
Luiz Carlos Sandoval Góes ◽  
Paulo José Paupitz Gonçalves
Keyword(s):  
Stability Analysis ◽  
Flight Control ◽  
Nonlinear Behavior ◽  
Computational Time ◽  
Benchmark Problems ◽  
Aeroelastic Flutter ◽  
Aeroelastic Model ◽  
Frequency Domain Methods ◽  
Space Formulation ◽  
New Methodologies

Most of the established procedures for analysis of aeroelastic flutter in the development of aircraft are based on frequency domain methods. Proposing new methodologies in this field is always a challenge, because the new methods need to be validated by many experimental procedures. With the interest for new flight control systems and nonlinear behavior of aeroelastic structures, other strategies may be necessary to complete the analysis of such systems. If the aeroelastic model can be written in time domain, using state-space formulation, for instance, then many of the tools used in stability analysis of dynamic systems may be used to help providing an insight into the aeroelastic phenomenon. In this respect, this paper presents a discussion on the use of Gramian matrices to determine conditions of aeroelastic flutter. The main goal of this work is to introduce how observability gramian matrix can be used to identify the system instability. To explain the approach, the theory is outlined and simulations are carried out on two benchmark problems. Results are compared with classical methods to validate the approach and a reduction of computational time is obtained for the second example.

Thermoacoustic Stability Analysis of a Full-Annular Lean Combustor for Heavy-Duty Applications

2021 ◽  
Author(s):  
Daniele Pampaloni ◽  
Antonio Andreini ◽  
Alessandro Marini ◽  
Giovanni Riccio ◽  
Gianni Ceccherini
Keyword(s):  
Stability Analysis ◽  
Gas Turbine ◽  
Flame Temperature ◽  
Numerical Procedure ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Heavy Duty ◽  
Operational Parameters ◽  
3D Fem ◽  
Wide Range

Abstract Thermoacoustic characterization of gas turbine combustion systems is of primary importance for successful development of gas turbine technology, to meet the stringent targets on pollutant emissions. In this context, it becomes more and more necessary to develop reliable tools to be used in the industrial design process. The dynamics of a lean-premixed full-annular combustor for heavy-duty applications has been numerically studied in this work. The well-established CFD-SI method has been used to investigate the flame response varying operational parameters such as the flame temperature (global equivalence ratio) and the fuel split between premixed and pilot fuel injections: such a wide range experimental characterization represents an opportunity to validate the employed numerical methods and to give a deeper insight into the flame dynamics. URANS simulations have been performed, due to their affordable computational costs from the industrial perspective, after validating their accuracy through the comparison against LES results. Furthermore, an approach where the pilot and the premixed flame responses are analyzed separately is proposed, exploiting the independence of their evolution. The calculated FTFs have been implemented in a 3D FEM model of the chamber, in order to perform linear stability analysis and to validate the numerical approach. A boundary condition for rotational periodicity based on Bloch-Wave theory has been implemented into the Helmholtz solver and validated against full-annular chamber simulations, allowing a significant reduction in computational time. The reliability of the numerical procedure has been assessed through the comparison against full-annular experimental results.

scholarly journals DIMENSIONAMENTO DE REDES DE DISTRIBUIÇÃO DE ÁGUA MALHADAS VIA OTIMIZAÇÃO POR ENXAME DE PARTÍCULAS

Irriga ◽  
2018 ◽  
Vol 23 (4) ◽  
pp. 798-817
Author(s):  
Saulo de Tarso Marques Bezerra ◽  
José Eloim Silva de Macêdo
Keyword(s):  
Particle Swarm Optimization ◽  
Optimization Algorithm ◽  
Distribution Systems ◽  
Water Distribution ◽  
Particle Swarm Optimization Algorithm ◽  
Particle Swarm ◽  
Computational Time ◽  
Benchmark Problems ◽  
Swarm Optimization ◽  
Irrigation Network

DIMENSIONAMENTO DE REDES DE DISTRIBUIÇÃO DE ÁGUA MALHADAS VIA OTIMIZAÇÃO POR ENXAME DE PARTÍCULAS     SAULO DE TARSO MARQUES BEZERRA1 E JOSÉ ELOIM SILVA DE MACÊDO2   1 Universidade Federal de Pernambuco, Campus Agreste, Núcleo de Tecnologia, Avenida Campina Grande, S/N, Bairro Nova Caruaru, CEP 55014-900, Caruaru, Pernambuco, Brasil. [email protected]. 2 Centro Universitário Maurício de Nassau, Departamento de Engenharia Civil, BR 104, Km 68, S/N, Bairro Agamenon Magalhães, CEP 55000-000, Caruaru, Pernambuco, Brasil. [email protected].     1 RESUMO   Apresenta-se, neste trabalho, um modelo de otimização para o dimensionamento de sistemas pressurizados de distribuição de água para projetos de irrigação. A metodologia empregada é fundamentada no algoritmo Otimização por Enxame de Partículas (PSO), que é inspirada na dinâmica e comportamento social observados em muitas espécies de pássaros, insetos e cardumes de peixes. O PSO proposto foi aplicado em dois benchmark problems reportados na literatura, que correspondem à Hanoi network e a um sistema de irrigação localizado na Espanha. O dimensionamento resultou, para as mesmas condições de contorno, na solução de ótimo global para a Hanoi network, enquanto a aplicação do PSO na Balerma irrigation network demonstrou que o método proposto foi capaz de encontrar soluções quase ótimas para um sistema de grande porte com um tempo computacional razoável.   Palavras-chave: água, irrigação, análise econômica.     BEZERRA, S. T. M.; MACÊDO, J. E. S. LOOPED WATER DISTRIBUTION NETWORKS DESIGN VIA PARTICLE SWARM OPTIMIZATION ALGORITHM     2 ABSTRACT   This paper presents an optimization model for the design of pressurized water distribution systems for irrigation projects. The methodology is based on the Particle Swarm Optimization algorithm (PSO), which is inspired by the social foraging behavior of some animals such as flocking behavior of birds and the schooling behavior of fish. The proposed PSO has been tested on two benchmark problems reported in the literature, which correspond to the Hanoi network and an irrigation system located in Spain. The design resulted in the global optimum for the Hanoi network, while the application of PSO in Balerma irrigation network demonstrated that the proposed method was able to find almost optimal solutions for a large-scale network with reasonable computational time.   Keywords: water, irrigation, economic analysis. O desempenho do método foi comparado com trabalhos prévios, demonstrando convergência rápida e resultados satisfatórios na busca da solução ótima de um sistema com elevado exigência computacional.

Analytical Design and Stability Analysis of the Universal Integral Regulator Applied in Flight Control

2019 ◽  
Vol 17 (2) ◽  
pp. 391-404
Author(s):  
Yohan Díaz-Méndez ◽  
Marcelo S. de Sousa ◽  
Guilherme Gomes ◽  
Sebastião Cunha ◽  
Alexandre Ramos
Keyword(s):  
Stability Analysis ◽  
Flight Control ◽  
Analytical Design ◽  
Universal Integral

A Simultaneous Computing Framework for Metamodel-Based Design Optimization

2014 ◽  
Author(s):  
Teng Long ◽  
Lv Wang ◽  
Di Wu ◽  
Xiaosong Guo ◽  
Li Liu
Keyword(s):  
Design Optimization ◽  
Data Exchange ◽  
Optimization Problems ◽  
Configuration Software ◽  
Computational Time ◽  
Benchmark Problems ◽  
Distributed Data ◽  
Legacy Software ◽  
Distributed Framework ◽  
Hardware Configuration

At the aim of reducing the computational time of engineering design optimization problems using metamodeling technologies, we developed a flexible distributed framework independent of any third-part parallel computing software to implement simultaneous sampling during metamodel-based design optimization procedures. In this paper, the idea and implementation of hardware configuration, software structure, the main functional modular and interfaces of this framework are represented in detail. The proposed framework is capable of integrating black-box functions and legacy software for analyzing and common MBDO methods for space exploring. In addition, a message-based communication infrastructure based on TCP/IP protocol is developed for distributed data exchange. The Client/Server architecture and computing budget allocation algorithm considering software dependency enable samples to be effectively allocated to the distributed computing nodes for simultaneous execution, which gives rise to decreasing the elapsed time and improving MBDO’s efficiency. Through testing on several numerical benchmark problems, the favorable results demonstrate that the proposal framework can evidently save the computational time, and is practical for engineering MBDO problems.

Reduced Order Modeling for the Flutter Stability Analysis of a Highly Loaded Transonic Fan

2012 ◽  
Author(s):  
Markus May
Keyword(s):  
Stability Analysis ◽  
Reduced Order Modeling ◽  
Computational Time ◽  
Influence Coefficient ◽  
Cfd Simulations ◽  
Reduced Order ◽  
Flutter Boundary ◽  
Sampling Procedures ◽  
Transonic Fan ◽  
Highly Loaded

Reduced order modeling strategies are applied to the aeroelastic stability analysis of the highly loaded transonic DLR UHBR fan. Latin hypercube and risk-based sampling procedures are employed to choose samples in a multidimensional parameter space that enable an accurate prediction of the flutter boundary without performing unsteady CFD simulations for several modes in the whole operating range. The combination with an influence coefficient approach facilitates even further savings in terms of computational time without losing physics quality.

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