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At least 19 records

On Slender-Body Theory at Transonic Speeds

The basic ideas of the slender-body approximation have been applied to the nonlinear transonic-flow equation for the velocity potential in order to obtain some of the essential features of slender-body theory at transonic speeds. The results of the investigation are presented from a unified point of view which demonstrates the similarity of slender-body solutions in the various Mach number ranges. The transonic area rule and some conditions concerning its validity follow from the analysis. (author)

Harder, Keith C

On slender-body theory and the area rule at transonic speeds

The basic ideas of the slender-body approximation have been applied to the nonlinear transonic-flow equation for the velocity potential in order to obtain some of the essential features of slender-body theory at transonic speeds. The results of the investigation are presented from a unified point of view which demonstrates the similarity of slender-body solutions in the various Mach number ranges. The transonic area rule and some conditions concerning its validity follow from the analysis.

FLOW, SUPERSONIC

Slender-Body Theory Based On Approximate Solution of the Transonic Flow Equation

Approximate solution of the nonlinear equations of the small disturbance theory of transonic flow are found for the pressure distribution on pointed slender bodies of revolution for flows with free-stream, Mach number 1, and for flows that are either purely subsonic or purely supersonic. These results are obtained by application of a method based on local linearization that was introduced recently in the analysis of similar problems in two-dimensional flows. The theory is developed for bodies of arbitrary shape, and specific results are given for cone-cylinders and for parabolic-arc bodies at zero angle of attack. All results are compared either with existing theoretical results or with experimental data.

Spreiter, John R.

Second-Order Slender-Body Theory-Axisymmetric Flow

Slender-body theory for subsonic and supersonic flow past bodies of revolution is extended to a second approximation, Methods are developed for handling the difficulties that arise at round ends, Comparison is made with experiment and with other theories for several simple shapes.

VanDyke, Milton D.

Unsteady Aerodynamic Forces on a Slender Body of Revolution in Supersonic Flow

Linearized slender-body theory is applied to the computation of aerodynamic forces on an oscillating, or deforming, body in supersonic flow. The undeformed body is a body of revolution and the deformed body is represented by movement of a line through the centers of the cross sections which are assumed to remain circular. The time dependence is based on sinusoidal motion. For a body of vanishing thickness the slender-body theory yields the apparent mass approximation as it is obtained for incompressible crossflow around a cylinder. Both linearized slender-body theory and the apparent mass approximation are used to calculate the pitching-moment coefficients on a rigid slender body with a parabolic arc nose cone, and these coefficients are compared with some experimental results.

Bond, Reuben

Effect of Body Perturbations on Hypersonic Flow Over Slender Power Law Bodies

Hypersonic-slender-body theory, in the limit as the free-stream Mach number becomes infinite, is used to find the effect of slightly perturbing the surface of slender two-dimensional and axisymmetric power law bodies, The body perturbations are assumed to have a power law variation (with streamwise distance downstream of the nose of the body). Numerical results are presented for (1) the effect of boundary-layer development on two dimensional and axisymmetric bodies, (2) the effect of very small angles of attack (on tow[dimensional bodies), and (3) the effect of blunting the nose of very slender wedges and cones.

Mirels, Harold

A nonlinear theory for sonic-boom calculations in a stratified atmosphere

The exact solutions to the equations of gas dynamics are given with respect to the axis of slender lifting bodies in a stratified atmosphere. The boundary condition is satisfied by using slender-body theory. The solution predicts the magnitude of the pressure rise of the sonic boom and estimates the nonlinear effects in the vicinity of the cutoff point.

Schorling, M.

Aerodynamic Loads on Tails at High Angles of Attack and Sideslip

Results are presented for the loads and moments acting on the individual tail surfaces of a body-tail combination over a wide range of angles of attack and sideslip. The effects of forebody length and panel-panel interference on the characteristics are included. It is shown that large nonlinear variations in these loads and moments, which occur at some combinations of angle of attack and sideslip, cannot be predicted by low-angle theory. A relatively simple, but general, theoretical method for calculating these load and moment characteristics is described, and the results from this method are found to be in good agreement with experiment provided the initial positions of the forebody vortices are known. It is shown that a simple application of slender-body theory can be used to predict the side loads due to sideslip that are contributed by a vertical tail on a wide variety of wing-body-tail combinations at low angles of attack. For several configurations, changes are indicated which reduced the vertical-tail loads per unit yawing moment of each complete configuration at large angles of attack. Some results are presented on the effect of high angle of attack on the induced-flow field and tail loads due to a wing at supersonic speed.

SLENDER BODY

Theoretical lift due to wing incidence of slender wing-body-tail combinations at zero angle of attack

The theoretical lift of a cylindrical afterbody at zero angle of attack due to incidence of the wing is calculated by means of slender-body theory. It is assumed that the vortex sheet becomes fully rolled up ahead of the tail, and the vortex paths in the presence of the body are determined analytically. The total lift of a variety of slender wing-body-tail combinations due to wing incidence is also calculated.

LOADS - FUSELAGE, NACELLES, AND CANOPIES