• Login
    View Item 
    •   etd@IISc
    • Division of Mechanical Sciences
    • Aerospace Engineering (AE)
    • View Item
    •   etd@IISc
    • Division of Mechanical Sciences
    • Aerospace Engineering (AE)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Flutter Identification and Aeroelastic Stability during Wake Penetration

    View/Open
    Thesis-Abstract (46.34Kb)
    Thesis-Full Text (8.811Mb)
    Author
    Sudha, U P V
    Metadata
    Show full item record
    Abstract
    Demonstration of utter stability over the design envelope and identi fication of safe ight envelope is a prerequisite for operational clearance of any new aircraft design. An important step involved in flight flutter testing is the proper use of flutter prediction techniques to accurately predict flutter. This study focuses on flutter estimation techniques given flight test data. We review various flutter prediction techniques by simulating them on a three-degree-of-freedom aeroelastic system. We show that flutter margin and an auto-regressive model based approach are robust and reasonably accurate in predicting flutter onset. Using these two techniques, flutter margins are computed at flight test points obtained from flight test data of flexible aircraft. Throughout, we have predicted flutter dynamic pressure at constant Mach number. One of the contributions of this work is in predicting flutter dynamic pressure at transonic Mach numbers. A critical issue in flutter prediction is the lack of information on the flutter instability mode and thereby the number of modes to include in a model. In a novel application of tools from statistical signal processing, we determine the optimum model order to construct an auto-regressive model using the flight flutter test time response data. From this auto-regressive model the frequency and damping values are estimated which in turn is used to estimate aeroelastic stability parameters. High resolution property of auto-regressive technique even with short data records is demonstrated in this thesis. This will provide a quick evaluation of spectral estimate and stability parameter using the same auto-regressive model, facilitating a quick envelope expansion. Aeroelastic stability during wake penetration is an essential part of operational clearance of new aircraft. In this thesis, and perhaps one of the first such study, wake flight test response data is used to assess the stability of the aircraft during wake penetration by modeling the wake response data in an auto-regressive framework. We have compared analytical predictions of incremental load factor based on simulations with flight tests on wake interactions. Estimates for safe wake encounter distance that do not exceed structural limit load factors have been determined.
    URI
    https://etd.iisc.ac.in/handle/2005/4799
    Collections
    • Aerospace Engineering (AE) [420]

    Related items

    Showing items related by title, author, creator and subject.

    • Flutter Susceptibility Assessment of Airplanes in Sub-critical Regime using Ameliorated Flutter Margin and Neural Network Based Methods 

      Kumar, Brijesh (2018-02-17)
      As flight flutter testing on an airplane progresses to high dynamic pressures and high Mach number region, it becomes very difficult for engineers to predict the level of the remaining stability in a flutter-prone mode and ...
    • Study Of Stall Flutter Of An Isolated Blade In A Low Reynolds Number Incompressible Flow 

      Bhat, Shantanu (2015-07-08)
      Highly-loaded turbomachine blades can stall under off-design conditions. In this regime, the flow can separate close to the leading edge of the blade in a periodic manner that can lead to blade vibrations, commonly referred ...
    • Some Investigations On Supersonic Flutter And Tailoring Of Laminated Composite Skin Panels 

      Vijay, B V (2012-11-07)

    etd@IISc is a joint service of SERC & J R D Tata Memorial (JRDTML) Library || Powered by DSpace software || DuraSpace
    Contact Us | Send Feedback | Thesis Templates
    Theme by 
    Atmire NV
     

     

    Browse

    All of etd@IIScCommunities & CollectionsTitlesAuthorsAdvisorsSubjectsBy Thesis Submission DateThis CollectionTitlesAuthorsAdvisorsSubjectsBy Thesis Submission Date

    My Account

    LoginRegister

    etd@IISc is a joint service of SERC & J R D Tata Memorial (JRDTML) Library || Powered by DSpace software || DuraSpace
    Contact Us | Send Feedback | Thesis Templates
    Theme by 
    Atmire NV