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Tuesday, May 19, 2020 | History

3 edition of Method for experimental determination of flutter speed by parameter identification found in the catalog.

Method for experimental determination of flutter speed by parameter identification

Method for experimental determination of flutter speed by parameter identification

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  • 16 Currently reading

Published by National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Division, For sale by the National Technical Information Service in [Washington, D.C.], Springfield, VA .
Written in English

    Subjects:
  • Flutter (Aerodynamics) -- Mathematical models.,
  • Aeroelasticity.,
  • Dynamic pressure.,
  • Flight tests.,
  • Flutter.,
  • Parameter identification.

  • Edition Notes

    StatementE. Nissim and Glenn B. Gilyard.
    SeriesNASA technical paper -- 2923.
    ContributionsGilyard, Glenn B., United States. National Aeronautics and Space Administration. Scientific and Technical Information Division.
    The Physical Object
    FormatMicroform
    Paginationiii, 40 p.
    Number of Pages40
    ID Numbers
    Open LibraryOL16123560M

      For the experimental determination of dynamic derivatives a new method is presented. Instead of sinusoidal oscillations the models undergoes specifically designed maneuvers on the wind tunnel’s 6 DOF model support. For data evaluation the parameter identification method, as used in flight testing, is by: 1. Iterative Least Squares (ILS) method was employed for identifying the flutter derivatives of the multibox bridge deck model, based on the results obtained from the free vibration tests and based on the frequency analysis the critical flutter wind speed for the corresponding prototype of the multibox bridge was estimated at m/ by: 1.

    For more conventional design aircraft, body freedom flutter tends to appear less frequently, however it should not be dismissed. Below is what this vehicle looks like when it reaches its flutter speed: When using NASTRAN’s solution , body freedom flutter can be incorporated by simply running a model without any constraints. The LibreTexts libraries are Powered by MindTouch ® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. We also acknowledge previous National Science Foundation support under grant numbers , , and

    Problem statement: Flutter derivatives are the essential parameters in the estimations of the flutter critical wind velocity and the responses of long-span cable supported bridges. These derivatives can be experimentally estimated from wind tunnel test results. Generally, wind tunnel test methods can be divided into free decay test and buffeting by: 3. Improved Understanding of Transonic Flutter: a Three Parameter Flutter Surface Denis B. Kholodar, United States Air Force Academy, Colorado Springs, CO Earl H. Dowell y, Je rey P. Thomas z, and Kenneth C. Hall x Duke University, Durham, NC An understanding of transonic utter is often critical for highspeed aircraft develop-ment.


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Method for experimental determination of flutter speed by parameter identification Download PDF EPUB FB2

Method for Experimental Determination of Flutter SPeed by Parameter Iden tification Author: Nissim, E. and Gilyard, Glenn B. Subject: NASA TP Keywords: Flutter testing, Parameter identification Created Date: 7/10/ PM.

A method for flight flutter testing is proposed which enables one to determine the flutter dynamic pressure from flights flown far below the flutter dy- namic pressure.

The method is based on the identi- fication of the coefficients of the equations of motion at low. A method for flight flutter testing is proposed which enables one to determine the flutter dynamic pressure from flights flown far below the flutter dynamic pressure.

The method is based on the identification of the coefficients of the equations of motion at low dynamic pressures, followed by the solution of these equations to compute the flutter dynamic : Glenn B.

Gilyard and E. Nissim. A method for flight flutter testing is proposed which enables one to determine the flutter dynamic pressure from flights flown far below the flutter dynamic pressure. The method is based on the identification of the coefficients of the equations of motion at low dynamic pressures, followed by the solution of these equations to compute the flutter dynamic pressure.

Safe Flutter Tests Using Parametric Flutter Margins. “ Method for Experimental Determination of Flutter Speed by Parameter Identification,” AIAA PaperLink Google Scholar [6] Cooper J.

E., Emmett P. R., Wright J. and Schofield M. J., Cited by: 1. Flutter parameters are estimated using system identification methods; A decision is made to proceed to the next flight test point or not. The main task of these flight tests is to predict stability at the next test speed with confidence, allowed by estimating aeroelastic parameters (stage two).

As the flutter speed is one of the most important instability parameters of a structure, and the flutter instability can cause catastrophic failure, different methods to predict the flutter speed have been developed and proposed so far. Normally studies on aeroelastic systems are treated in either the frequency or the time by: 9.

calculated flutter speed for the existing store configurations. Parameter Flutter Solver (NASTRAN Sol) Spline EM grid to UA grid Flutter Results Experimental Modal FLUTTER ANLAYSIS OF F AIRCRAFT UTILIZING TEST MODAL DATA set of grounded springs in plunge (K P) and roll (K R) could then be written as.

Flutter is a dynamic instability problem represents the interaction among structural, aerodynamic, elastic and inertial forces and occurred when the energy is continuously transformed by the surrounding fluids to a flying structure in the form of kinetic energy.

The study was conducted to investigate the relationship of the control surface deflection angle to the flutter speed and the flutter Author: Muhammad Iyas Mahzan, Sallehuddin Muhamad, Sa’ardin Abdul Aziz, Mohamed Sukri Mat Ali.

The Zimmerman–Weissenburger method utilizes the coupled equation of motion, applies the Routh stability criterion using a quadratic stability parameter, and solves for the flutter margin (Zimmerman and Weissenburger, ). However, its application is limited to 2 degrees of freedom (the classical bending torsion flutter) with quasi-steady by: The method investigated in the current research work is based on the identification of the equations of motion during test flights, followed by the solution of these identified equations to numerically compute the flutter dynamic by: 1.

Identification of flutter derivatives by forced vibration tests (1) (2) In these equations, ρ is the air density, is the undisturbed or U mean oncoming wind velocity,B is the section width, K=Bω/U is the reduced frequency, and H i *, A i * (i=) are the flutter derivatives.

A set of flutter File Size: 1MB. Get this from a library. Method for experimental determination of flutter speed by parameter identification. [E Nissim; Glenn B Gilyard; United States.

National Aeronautics and Space Administration. Scientific and Technical Information Division.]. It is found that, for simple aeroelastic systems, the Nissim and Gilyard method (Nissim, E., and Gilyard, G.

B., “Method for Experimental Determination of Flutter Speed by Parameter Identification,” AIAA Paper) yields the best flutter predictions and is also the least computationally expensive r, for larger Cited by: Variation of flutter speed with elevator mass balance weight m.

1 2 3 1 methods used in making flutter calculations. A memorandum" was written at the time describing these methods. Although memorandum was necessarily limited in scope, it has proved to be of considerable value and experimental and theoretical work isFile Size: 3MB.

The method investigated in the current research work is based on the identification of the equations of motion during test flights, followed by the solution of these identified equations to numerically compute the flutter dynamic pressure.

The current research work is aimed at overcoming two main difficulties which arise when: 1. Considerations of a Flutter Prediction Methodology Using a Combined Analytical-experimental Procedure. Authors; H., and Roubertier, J.

() Advanced parameter identification techniques for near real time Nissim, E. and Gilyard, G.B. () Method for experimental determination of flutter speed by parameter identification, NASA-TPAuthor: Piergiovanni Marzocca, Liviu Librescu, Walter A. Silva. I do question regarding Dart and Flutter.

So I'm trying to refactor some code and I'm stuck in a referencing problem. Flutter function parameter pass by reference. Ask Question Asked 1 year, 2 months ago. Active 1 year, 2 months ago.

Viewed 9k times 3. I do question regarding Dart and Flutter. I'm trying to create a function called. It is found that, for simple aeroelastic systems, the Nissim and Gilyard method (Nissim, E., and Gilyard, G. B., "Method for Experimental Determination of Flutter Speed by Parameter Identification.

A theory is given for the determination of the flutter frequency and speed of a hydrofoil traveling at a constant speed. This work used the work of Sears to determine the fluctuating lift and combined it with the chordwise and transverse drag forces to determine flutter by: 1.

the repired aerodynamic coefficients, V is the flutter speed, w is the flutter freqenoy and q, ad q2 sre the generalised co-ordinates. It is assumea in equations (1) that there are no cross structural dsmpings or stiffnesses. At flutter we msy replace q, by e iwt and 42 by Ke dwt-$1 where K= 22 I 91 1, 'File Size: KB.Experimental Determination of Unsteady Aerodynamic Coefficients and Flutter Behavior of a Rigid Wing system identification method to generate a reduced-order.

Flutter Prediction from Flight Flutter Test Data. Experimental determination of unsteady aerodynamic coefficients and flutter behavior of a rigid wing. Journal of Fluids and Structures, Vol. Flutter-Margin Method Accounting for Modal Parameters by: