M.Sc Thesis

M.Sc StudentLaniado Fein Moran
SubjectSlender Bodies Moving in Close Proximity to a Wing
DepartmentDepartment of Aerospace Engineering
Supervisor RESEARCH PROFESSOR E Daniel Weihs
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


The structure of slender bodies in proximity to a wing is frequently used by aircraft in various configurations. Different examples of this application are wing-hung armaments, fuel tanks and intelligence devices.

An engineering design of such a configuration must account for several factors; the structures influence on the wing's strength, stability, case of release, etc. Efficient aerodynamic design can improve the drag-lift ratio of the configuration.

Previous studies have shown that when slender bodies are in proximity to each other, interaction forces and moments are created on the bodies.

The objective of this study is to investigate the wing's effect on the forces created by the interaction between two slender bodies in proximity. From the results, principles for efficient design and aerodynamic optimization for the configuration of slender bodies in proximity to a wing can be derived. The experiments were carried out in the Subsonic Wind Tunnel (#14) in the Technion's Aerospace Engineering Faculty.

The forces that effect slender objects in proximity to each other and in proximity to a wing have been tested in different structure formations including different longitudinal and lateral distances of the slender bodies from the wing.

One of the main conclusions derived from this study is that when two slender bodies move in proximity to each other with no longitudinal distance between them, the drag can be decreased by 20%. The different positioning of the bodies in relation to the wing has a significant effect on drag. Drag is greatly reduced when the body is positioned after the leading edge of the wing, as compared to a body positioned in front of the leading edge of the wing. Yet both the side and vertical forces applied to the bodies greatly increase when the bodies are placed in front of the leading edge of the wing.

The wings effect on the forces acting on the bodies in the axial and normal direction starts at a distance of one chord between centers of the bodies to the center of the wing.

The wings effect on the lateral force starts much closer to the wing around third chord.

The wing effect is more noticeable in the horizontal configuration compared to the vertical configuration.