Journal ArticleDOI
Application of Transonic Codes to Flutter Analysis of Conventional and Supercritical Airfoils
TLDR
In this paper, the effect of Mach number on transonic flutter speed was studied for several values of four different aeroelastic parameters, including angle of attack, angle of freedom, and CAST 7.Abstract:
Transonic flutter analyses are performed for two conventional airfoils, NACA 64A006 and NACA 64A010, and three supercritical airfoils, MBB A-3, CAST 7, and the NASA TF-8A wing section at 65.3% semispan. Two degrees of freedom, plunging and pitching about the quarter-chord axis, are considered. The aerodynamic data are obtained by using the two transonic aerodynamics codes LTRAN2 (indicial and time integration methods) and STRANS2/UTRANS2 (harmonic analysis method). The unsteady aerodynamic data are computed within the low reduced frequency range. For all airfoils, the effect of Mach number on flutter speed is studied for several values of four different aeroelastic parameters. For the MBB A-3 supercritical airfoil, the effect of angle of attack on flutter speed is studied. For the cases of a flat plate and a NACA 64A006 airfoil, time response results are obtained by LTRAN2. Applicability and limitations of the two transonic codes are evaluated. Results for the transonic flutter characteristics of these airfoils are discussed and some comparisons are made. ah b,cread more
Citations
More filters
Journal ArticleDOI
Time-marching transonic flutter solutions including angle-of-attack effects
TL;DR: In this article, a transonic small perturbation potential equation was used to determine transonic flutter boundaries versus Mach number and angle of attack for NACA 64A010 and MBB A-3 airfoils.
Journal ArticleDOI
Transonic and low-supersonic aeroelastic analysis of a two-degree-of-freedom airfoil with a freeplay non-linearity
Dong-Hyun Kim,In Lee +1 more
TL;DR: In this paper, a two-degree-of-freedom airfoil with a free-play nonlinearity in the pitch and plunge directions has been analyzed in the transonic and low-supersonic flow region, where aerodynamic nonlinearities also exist.
Journal ArticleDOI
Flutter Analysis Using Nonlinear Aerodynamic Forces
T. Ueda,Earl H. Dowell +1 more
TL;DR: In this paper, the effects of transonic aerodynamic forces on the flutter boundary of a typical section airfoil were studied by utilizing a novel variation of the describing function method which takes into account the first fundamental harmonic of the nonlinear oscillatory motion.
References
More filters
Journal ArticleDOI
Computation of Unsteady Transonic Flows by the Indicial Method
TL;DR: In this article, the indicial method is used for the computation of unsteady transonic force and moment coefficients for use in flutter analyses. But it is not suitable for the analysis of aeroelastic systems.
Investigations of the transonic flow around oscillating airfoils
TL;DR: In this paper, an experimental analysis of high-subsonic and transonic flow on a conventional airfoil with oscillating flap and a supercritical airframe oscillating in pitch is presented, where the interaction between the steady and unsteady flow fields, the periodical motion of the shock waves and their contribution to the overall unstrainy airloads are discussed.
Journal ArticleDOI
Implicit Finite-Difference Computations of Unsteady Transonic Flows about Airfoils
TL;DR: In this paper, a computer code, LTRAN2, has been constructed that efficiently computes low-frequency unsteady transonic flows about airfoils in motion.
Journal ArticleDOI
On the Transonic-Dip Mechanism of Flutter of a Sweptback Wing
TL;DR: In this paper, Cebeci, T. and Stewartson, K. proposed a new boundary layer separation technique based on boundary-layer theory and showed that it is possible to predict the separation of a Laminar Boundary Layer using boundary layer theory.
Journal ArticleDOI
Role of Shocks in the "Sub-Transonic" Flutter Phenomenon
TL;DR: In this paper, the influence of partial-chord transonic shocks on flutter of "typical-section" wing models was investigated, where unsteady airloads were assumed as the sum of linearized theory and a "shockforce doublet" centered at the measured steady shock location.