Lifting-surface theory for a wing oscillating in yaw and sideslip with an angle of attack.

AIAA Journal ◽  
1973 ◽  
Vol 11 (5) ◽  
pp. 599-606 ◽  
Author(s):  
KOJI ISOGAI ◽  
TERUO ICHIKAWA
Keyword(s):  
Angle Of Attack ◽  
Surface Theory ◽  
Lifting Surface

Unsteady Linearized Lifting-Surface Theory in the Presence of a Free Surface

1987 ◽  
Vol 31 (03) ◽  
pp. 151-163
Author(s):  
J. Leclerc ◽  
P. Salaun
Keyword(s):  
Integral Equation ◽  
Free Surface ◽  
Unknown Function ◽  
Pressure Difference ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Thin Structures ◽  
Surface Theory ◽  
Lifting Surface ◽  
The Right

A new lifting-surface theory is developed for the computation of three-dimensional hydrodynamic pressures on thin structures in the presence of a free surface. Two interesting cases are treated: the steady case and the supercritical unsteady case. The theory is linearized and the problem is reduced to the solution of an integral equation where the unknown function is the pressure difference between the elements of the structure and the right-hand side the angle of attack. Forces and moments are presented in both the steady and unsteady cases. This theory allows the analysis of flutter and the study of steady drag and of the turn of ships.

Unsteady Lifting Surface Theory for a Rotating Cascade of Swept Blades

1989 ◽  
Author(s):  
Hidekazu Kodama ◽  
Masanobu Namba
Keyword(s):  
Three Dimensional ◽  
Acoustic Power ◽  
Aerodynamic Characteristics ◽  
Blade Loading ◽  
Surface Theory ◽  
Numerical Examples ◽  
Lifting Surface ◽  
Blade Flutter ◽  
Annular Cascade ◽  
Remarkable Reduction

A lifting surface theory is developed to predict the unsteady three-dimensional aerodynamic characteristics for a rotating subsonic annular cascade of swept blades. A discrete element method is used to solve the integral equation for the unsteady blade loading. Numerical examples are presented to demonstrate effects of the sweep on the blade flutter and on the acoustic field generated by interaction of rotating blades with a convected sinusoidal gust. It is found that increasing the sweep results in decrease of the aerodynamic work on vibrating blades and also remarkable reduction of the modal acoustic power of lower radial orders for both forward and backward sweeps.

Lifting-Surface Theory for an Oscillating T-Tail

AIAA Journal ◽  
1974 ◽  
Vol 12 (1) ◽  
pp. 28-37 ◽  
Author(s):  
KOJI ISOGAI
Keyword(s):  
Surface Theory ◽  
Lifting Surface

Derivation by a Transform Method of Integral Equations of Unsteady Lifting Surface Theory in Subsonic and Supersonic Flow

1979 ◽  
Vol 30 (4) ◽  
pp. 529-543
Author(s):  
Shigenori Ando ◽  
Akio Ichikawa
Keyword(s):  
Fourier Transforms ◽  
Integral Transforms ◽  
Physical Models ◽  
Streamwise Direction ◽  
Fourier Inversion ◽  
Transform Method ◽  
Inviscid Flows ◽  
Surface Theory ◽  
Method Of Integral Equations ◽  
Lifting Surface

SummaryApplications of “integral transforms of in-plane coordinate variables” in order to formulate unsteady planar lifting surface theories are demonstrated for both sub- and supersonic inviscid flows. It is concise and pithy. Fourier transforms are exclusively used, except for only Laplace transform in the supersonic streamwise direction. It is found that the streamwise Fourier inversion in the subsonic case requires some caution. Concepts based on the theory of distributions seem to be essential, in order to solve the convergence difficulties of integrals. Apart from this caution, the method of integral transforms of in-plane coordinate variables makes it be pure-mathematical to formulate the lifting surface problems, and makes aerodynamicist’s experiences and physical models such as vortices or doublets be useless.

Some Remarks on Vortex Drag and its Spanwise Distribution in Incompressible Flow

1968 ◽  
Vol 72 (691) ◽  
pp. 623-625 ◽  
Author(s):  
H. C. Garner
Keyword(s):  
Theoretical Data ◽  
Leading Edge ◽  
List Type ◽  
Surface Theory ◽  
Lifting Surface ◽  
Line Theory ◽  
Lifting Line ◽  
Swept Wings ◽  
Lifting Line Theory ◽  
Drag Factor

Summary Theoretical data from lifting-surface theory are presented to illustrate (i) that the vortex drag factor is closely related to the half-wing spanwise centre of pressure on simple planforms without camber or twist, (ii) that lifting-line theory is useless for predicting the spanwise distribution of vortex drag on swept wings, (iii) that recent numerical improvements in lifting-surface theory help to reconcile the concepts of wake energy and leading-edge suction in relation to vortex drag.

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