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.

Modal decomposition-based global stability analysis for reduced order modeling of 2D and 3D wake flows

2015 ◽  
Vol 81 (3) ◽  
pp. 178-191 ◽  
Author(s):  
Witold Stankiewicz ◽  
Marek Morzyński ◽  
Krzysztof Kotecki ◽  
Robert Roszak ◽  
Michał Nowak
Keyword(s):  
Stability Analysis ◽  
Global Stability ◽  
Reduced Order Modeling ◽  
Modal Decomposition ◽  
Reduced Order ◽  
Wake Flows ◽  
Global Stability Analysis ◽  
2D And 3D

scholarly journals Industrial Digital Twins based on the non-linear LATIN-PGD

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Philippe Barabinot ◽  
Ronan Scanff ◽  
Pierre Ladevèze ◽  
David Néron ◽  
Bruno Cauville
Keyword(s):  
Finite Element ◽  
High Performance ◽  
Reduced Order Modeling ◽  
Computational Time ◽  
Reduced Order ◽  
Finite Element Software ◽  
Digital Twins ◽  
Non Linear ◽  
Industrial Level ◽  
Early Design Phase

AbstractDigital Twins, which tend to intervene over the entire life cycle of products from early design phase to predictive maintenance through optimization processes, are increasingly emerging as an essential component in the future of industries. To reduce the computational time reduced-order modeling (ROM) methods can be useful. However, the spread of ROM methods at an industrial level is currently hampered by the difficulty of introducing them into commercial finite element software, due to the strong intrusiveness of the associated algorithms, preventing from getting robust and reliable tools all integrated in a certified product. This work tries to circumvent this issue by introducing a weakly-invasive reformulation of the LATIN-PGD method which is intended to be directly embedded into Simcenter Samcef$$^{\hbox {TM}}$$ TM finite element software. The originality of this approach lies in the remarkably general way of doing, allowing PGD method to deal with not only a particular application but with all facilities already included in such softwares—any non-linearities, any element types, any boundary conditions...—and thus providing a new high-performance all-inclusive non-linear solver.

Investigation of Inlet Distortion on the Flutter Stability of a Highly Loaded Transonic Fan Rotor

2016 ◽  
Author(s):  
Senad Iseni ◽  
Derek Micallef ◽  
Ronald Mailach
Keyword(s):  
Three Dimensional ◽  
Wave Mode ◽  
Operating Point ◽  
Influence Coefficient ◽  
Worst Case ◽  
Inlet Distortion ◽  
Influence Coefficients ◽  
The Stability ◽  
Transonic Fan ◽  
Highly Loaded

The fundamental mechanisms of blade flutter in modern aircraft engines are very complex. Flutter is a self-excited aeroelastic instability phenomenon which can finally cause material fatigue and, in the worst case, leads to blade failure within a very short time. The risk of flutter has to be considered during the design process and it is necessary to avoid that safety risk. The aeroelastic stability has to be ensured over the whole operating range especially near operating limits or typical flutter boundaries, like at stall or choke conditions. Topic of this paper are inlet distortions, which can have an additional influence on the flutter stability of the fan and the first compressor stages of jet engines. For this purpose a sinusoidal steady total pressure inlet distortion was defined. The influence of this inlet distortion on the flow field and the flutter stability of a highly loaded transonic fan rotor (NASA rotor 67) is investigated. The static deflection of the manufactured blade was considered using an accurate mesh morphing algorithm to update the fan performance characteristic considering the deformed blade structure. The fan rotor interacts with the upstream distorted flow which leads to different blade loading between the adjacent blades. A decoupled flutter stability analysis using the three-dimensional viscous flow solver TBLOCK and the open-source software package CalculiX for pre-stressed modal analyses is carried out. The flutter stability analyses with TBLOCK are performed using the so-called energy method which was introduced by Carta. In order to predict the flutter stability under clean inflow conditions, two different formulations, the Influence Coefficient Method (ICM) and Traveling Wave Mode (TWM) formulation, are taken into account, whereas both formulations are compared to each other. The influence coefficients were directly calculated from the TWM formulation to determine the required number of passages for the ICM. It can be seen that the stability curves obtained with the ICM are in a good agreement to the TWM-method. The use of ICM reduces substantially the number of unsteady CFD calculations because of the fact that only one unsteady CFD calculation is needed to reconstruct the stability curve for each eigenmode and operating point. The effect of inlet distortion on flutter stability is investigated applying the TWM formulation only. Indeed, it was established that such flow disturbances have also for specific blades, considering the operating point, eigenmode and nodal diameter a destabilising impact on their aeroelastic behavior and can cause flutter, which is mostly determined by the time-averaged stability parameter. Just in the same manner a positive effect was observed for certain blades in the blade row.

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