Investigation of Mistuning Effects on Cascade Flutter Using a Coupled Method

2007 ◽  
Vol 23 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Mani Sadeghi ◽  
Feng Liu
Keyword(s):  
Coupled Method ◽  
Cascade Flutter

Investigation of Mistuned Oscillating Cascade Using Fully-Coupled Method

2021 ◽  
Author(s):  
H. M. Phan ◽  
L. He
Keyword(s):  
Striking Difference ◽  
Influence Coefficient ◽  
Aeroelastic Stability ◽  
Mode Localization ◽  
Coupled Method ◽  
Reduced Frequency ◽  
Systematic Understanding ◽  
Cascade Flutter ◽  
The Individual ◽  
Fully Coupled

Abstract The uncoupled phase-shifted single-passage simulation is commonly used for turbomachinery aeroelastic problems. However, it has difficulties in dealing with unconventional phenomena such as strong fluid-structure interaction effects as well as blade mistuning effects. Regarding mistuning effects, structural mistuning has been studied extensively while aerodynamic mistuning has received far less attention. There seems to be a lack of clear and systematic understanding of physical behaviour and mechanisms of mistuned bladerows, particularly in the context of the aerodynamic mistuning versus structural one. In the present work, direct fully-coupled method is adopted to investigate the dynamics mechanism of a mistuned oscillating cascade. Both structurally and aerodynamically mistuned cascades show that the blades would couple and oscillate at a unique frequency and a constant inter-blade phase angle regardless of the individual blade’s eigen-frequency. The vibration amplitudes of blades of a mistuned row are different when excited. For structural mistuning, the mode localization effect is seen to be responsible for a monotonic increase of cascade aeroelastic stability with mistuning. On the other hand, the aerodynamically mistuned cascade shows a stabilizing effect at small amount of mistuning but exhibits a destabilizing effect at large mistuning. Such non-monotonic tendency could be explained using the aero-damping decomposition by the influence coefficient approach. At low reduced frequency, there is a striking difference between the tuned and aero-mistuned cascade. Although the tuned cascade is stable, the aero-mistuned cascade may experience flutter. A close inspection of the aero-mistuned cascade flutter reveals that there are two oscillating waves forming a beating signal.

Investigation of mistuning effects on cascade flutter using a coupled method

2002 ◽  
Author(s):  
M. Sadeghi ◽  
F. Liu ◽  
K. Gupta ◽  
L. Voelker ◽  
C. Bach
Keyword(s):  
Coupled Method ◽  
Cascade Flutter

Finite element method estimation of temperature distribution of automotive tire using one-way-coupled method

2021 ◽  
pp. 095440702110087
Author(s):  
Zumrat Usmanova ◽  
Emin Sunbuloglu
Keyword(s):  
Thermal Analysis ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Complex Geometry ◽  
Rolling Resistance ◽  
Operating Conditions ◽  
Deformation Analysis ◽  
Coupled Method ◽  
Experimental Values ◽  
Hysteretic Loss

Numerical simulation of automotive tires is still a challenging problem due to their complex geometry and structures, as well as the non-uniform loading and operating conditions. Hysteretic loss and rolling resistance are the most crucial features of tire design for engineers. A decoupled numerical model was proposed to predict hysteretic loss and temperature distribution in a tire, however temperature dependent material properties being utilized only during the heat generation analysis stage. Cyclic change of strain energy values was extracted from 3-D deformation analysis, which was further used in a thermal analysis as input to predict temperature distribution and thermal heat generation due to hysteretic loss. This method was compared with the decoupled model where temperature dependence was ignored in both deformation and thermal analysis stages. Deformation analysis results were compared with experimental data available. The proposed method of numerical modeling was quite accurate and results were found to be close to the actual tire behavior. It was shown that one-way-coupled method provides rolling resistance and peak temperature values that are in agreement with experimental values as well.

Assay of Nucleoside Diphosphate Kinase in Microtiter Plates Using a Peroxidase-Coupled Method

1993 ◽  
Vol 209 (1) ◽  
pp. 6-8 ◽  
Author(s):  
I. Lascu ◽  
K. Leblay ◽  
M.L. Lacombe ◽  
E. Presecan ◽  
M. Veron
Keyword(s):  
Nucleoside Diphosphate Kinase ◽  
Coupled Method ◽  
Microtiter Plates

scholarly journals A stabilized coupled method and its optimal error estimates for elliptic interface problems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Jiaping Yu ◽  
Feng Shi ◽  
Jianping Zhao
Keyword(s):  
Error Estimates ◽  
Numerical Experiments ◽  
Interface Problems ◽  
Optimal Error Estimates ◽  
Computational Stability ◽  
Optimal Error ◽  
Stabilized Method ◽  
Elliptic Interface Problems ◽  
Coupled Method

Abstract In this paper, we present a stabilized coupled algorithm for solving elliptic interface problems, mainly by introducing the jump of the solutions along the interface. A framework of theoretical proofs is provided to show the optimal error estimates of this stabilized method. Several numerical experiments are carried out to demonstrate the computational stability and effectiveness of the method.

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