scholarly journals Reduced order model for unsteady aerodynamic performance of compressor cascade based on recursive RBF

2020 ◽  
Author(s):  
Jiawei HU ◽  
Hanru LIU ◽  
Yan'gang WANG ◽  
Weixiong CHEN ◽  
Yan MA
Keyword(s):  
Aerodynamic Performance ◽  
Reduced Order Model ◽  
Compressor Cascade ◽  
Order Model ◽  
Reduced Order ◽  
Unsteady Aerodynamic

A Physically Consistent Reduced Order Model for Plasma Aeroelastic Control on Compressor Blades

2018 ◽  
Author(s):  
Valentina Motta ◽  
Leonie Malzacher ◽  
Dieter Peitsch ◽  
Giuseppe Quaranta
Keyword(s):  
Suction Side ◽  
Reduced Order Model ◽  
Plasma Actuators ◽  
Pitching Moment ◽  
Compressor Cascade ◽  
Order Model ◽  
Compressor Blades ◽  
Reduced Order ◽  
Thin Airfoil ◽  
Pressure Suction

Plasma actuators may be successfully employed as virtual control surfaces, located at the trailing edge of blades, both on the pressure and on the suction side, to control the aeroelastic response of a compressor cascade. Actuators generate an induced flow against the direction of the freestream. As a result, actuating on the pressure side yields an increase in lift and nose down pitching moment, whereas the opposite is obtained by operating on the suction side. A properly phased alternate pressure/suction side actuation allows to reduce vibration and to delay the flutter onset. This paper presents the development of a linear frequency domain reduced order model for lift and pitching moment of the plasma-equipped cascade. Specifically, an equivalent thin airfoil model is used as a physically consistent basis for the model. Modifications in the geometry of the thin airfoil are generated to account for the effective chord and camber changes induced by the plasma actuators, as well as for the effects of the neighboring blades. The model reproduces and predicts correctly the mean and the unsteady loads, along with the aerodynamic damping on the plasma equipped cascade. The relationship between the parameters of the reduced order model with the flow physics is highlighted.

A Reduced Order Model of Unsteady Flows in Turbomachinery

1994 ◽  
Author(s):  
Kenneth C. Hall ◽  
Răzvan Florea ◽  
Paul J. Lanzkron
Keyword(s):  
Fluid Motion ◽  
Unsteady Flows ◽  
Reduced Order Model ◽  
Lanczos Algorithm ◽  
Order Model ◽  
Reduced Order ◽  
Unsteady Aerodynamic ◽  
Natural Modes ◽  
Wide Range ◽  
Modes Of Vibration

A novel technique for computing unsteady flows about turbomachinery cascades is presented. Starting with a frequency domain CFD description of unsteady aerodynamic flows, we form a large, sparse, generalized, non-Hermitian eigenvalue problem which describes the natural modes and frequencies of fluid motion about the cascade. We compute the dominant left and right eigenmodes and corresponding eigenfrequencies using a Lanczos algorithm. Then, using just a few of the resulting eigenmodes, we construct a reduced order model of the unsteady flow field. With this model, one can rapidly and accurately predict the unsteady aerodynamic loads acting on the cascade over a wide range of reduced frequencies and arbitrary modes of vibration. Moreover, the eigenmode information provides insights into the physics of unsteady flows. Finally we note that the form of the reduced order model is well suited for use in active control of aeroelastic and aeroacoustic phenomena.

A Physically Consistent Reduced Order Model for Plasma Aeroelastic Control on Compressor Blades

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Valentina Motta ◽  
Leonie Malzacher ◽  
Victor Bicalho Civinelli de Almeida ◽  
Tien Dat Phan ◽  
Robert Liebich ◽  
...  
Keyword(s):  
Suction Side ◽  
Reduced Order Model ◽  
Plasma Actuators ◽  
Pitching Moment ◽  
Compressor Cascade ◽  
Order Model ◽  
Compressor Blades ◽  
Reduced Order ◽  
Thin Airfoil ◽  
Pressure Suction

Plasma actuators may be successfully employed as virtual control surfaces, located at the trailing edge (TE) of blades, both on the pressure and on the suction side, to control the aeroelastic response of a compressor cascade. Actuators generate an induced flow against the direction of the freestream. As a result, actuating on the pressure side yields an increase in lift and nose down pitching moment, whereas the opposite is obtained by operating on the suction side. A properly phased alternate pressure/suction side actuation allows to reduce vibration and to delay the flutter onset. This paper presents the development of a linear frequency domain reduced order model (ROM) for lift and pitching moment of the plasma-equipped cascade. Specifically, an equivalent thin airfoil model is used as a physically consistent basis for the model. Modifications in the geometry of the thin airfoil are generated to account for the effective chord and camber changes induced by the plasma actuators, as well as for the effects of the neighboring blades. The model reproduces and predicts correctly the mean and the unsteady loads, along with the aerodynamic damping on the plasma equipped cascade. The relationship between the parameters of the ROM with the flow physics is highlighted.

A Reduced Order Model of Unsteady Flows in Turbomachinery

1995 ◽  
Vol 117 (3) ◽  
pp. 375-383 ◽  
Author(s):  
K. C. Hall ◽  
R. Florea ◽  
P. J. Lanzkron
Keyword(s):  
Fluid Motion ◽  
Unsteady Flows ◽  
Reduced Order Model ◽  
Lanczos Algorithm ◽  
Order Model ◽  
Reduced Order ◽  
Unsteady Aerodynamic ◽  
Natural Modes ◽  
Wide Range ◽  
Modes Of Vibration

A novel technique for computing unsteady flows about turbomachinery cascades is presented. Starting with a frequency domain CFD description of unsteady aerodynamic flows, we form a large, sparse, generalized, non-Hermitian eigenvalue problem that describes the natural modes and frequencies of fluid motion about the cascade. We compute the dominant left and right eigenmodes and corresponding eigenfrequencies using a Lanczos algorithm. Then, using just a few of the resulting eigenmodes, we construct a reduced order model of the unsteady flow field. With this model, one can rapidly and accurately predict the unsteady aerodynamic loads acting on the cascade over a wide range of reduced frequencies and arbitrary modes of vibration. Moreover, the eigenmode information provides insights into the physics of unsteady flows. Finally we note that the form of the reduced order model is well suited for use in active control of aeroelastic and aeroacoustic phenomena.

Statistical Evaluation of the Performance Impact of Manufacturing Variations for Steam Turbines

2016 ◽  
Author(s):  
Juntao Xiong ◽  
Jing Yang ◽  
Ivan McBean ◽  
Said Havakechian ◽  
Feng Liu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Aerodynamic Performance ◽  
Reduced Order Model ◽  
Fast Method ◽  
Steam Turbines ◽  
Order Model ◽  
Machining Processes ◽  
Reduced Order ◽  
The Impact

A fast method is presented for evaluating the impact of blade manufacturing variations on the aerodynamic performance of turbomachines. The method consists of two parts. Firstly, an adjoint method is developed to evaluate the aerodynamic sensitivities for multistage turbomachines. This sensitivity information may then be used to perform fast direct Monte Carlo simulations to obtain the statistical distribution of the variations of aerodynamic performances resulting from any given set of manufacturing variations. Secondly, a method is developed to construct reduced-order models for the three-dimensional blades manufacturing variations using the Principal Component Analysis (PCA) method. Monte-Carlo simulations with the adjoint sensitivities can then be applied to the full and individual modes of the blade manufacturing deviations. The proposed method is applied to the last two stages of a low-pressure steam turbine. A total of 29 sets of measured manufacturing deviations of the last-stage rotor blades are used to construct a reduced-order model of the manufacturing variations. The manufacturing variation reduced-order model helps identify origins of the manufacturing deviations connected to the machining processes of the blades. Relations of the statistics of the aerodynamic performance variations such as mean, standard deviation, etc. to the different modes of manufacturing deviations are studied and analyzed.

Eigenmode Analysis in Unsteady Aerodynamics: Reduced Order Models

1997 ◽  
Vol 50 (6) ◽  
pp. 371-386 ◽  
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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