General Dynamics

About: General Dynamics is a company organization based out in Fairfax, Virginia, United States. It is known for research contribution in the topics: Signal & Propellant. The organization has 5722 authors who have published 5819 publications receiving 85768 citations. The organization is also known as: GD & General Dynamics Corporation.

Shielded eddy current sensor for enhanced sensitivity

Abstract: An eddy current sensor comprises a generally E-shaped core having three parallel legs joined together by a bridge. Current carrying coils are mounted on each of the outer legs and a signal coil is mounted on the central leg. Identical a.c. currents are caused to flow through the two outer coils for generating two magnetic fields which combine to form a sensing magnetic field extending outwardly from the ends of the legs for sensing purposes but which cancel one another within the central leg. The sensor is disposed within an E-shaped, hollow shield of an eddy current producing, electrically conductive material. The sensor fits within the shield as fingers in a glove with the parallel legs of the sensor magnetically separated from one another by walls of the shield. Only the ends of the sensor legs are exposed through apertures through the shield for emergence of the various magnetic fields. The shield cancels unwanted fringing fields and better guides the magnetic fields in desired directions.

Exhaust plumes from nozzles with wall boundary layers.

Abstract: Numerical computations of exhaust plume flowfields from nozzles with boundary layers along the wall are presented. The problem is treated as the inviscid expansion of a shear flow around the nozzle lip, in a manner reminiscent of treatments of the near wakes of reentry vehicles. The low-Mach-number gas near the wall expands well beyond the limiting line calculated without boundary-layer effects, and "observables" such as dynamic pressure are greatly increased in the large-angle region over the values predicted for a frictionless nozzle flow. The distributions of dynamic pressure in the large-angle region are not greatly sensitive to the details of the boundary-layer profiles at the exit plane, although there is a noticeable difference in behavior between laminar and turbulent layers. Large-angle (up to 90-100°) effects of fully developed laminar or turbulent layers probably can be predicted to within a factor of 2 or 3, whereas there are order-of-magnitude differences from the flow with no boundary layer.

Method of fabrication of fiber optic coupler

Abstract: A low-loss bidirectional optical coupler is provided by mounting together and joining with epoxy resin two like fiber optic elements in face-to-face relationship along a common plane Each of the elements is fabricated by affixing a portion of an optical fiber with epoxy resin along the curved surface of a solid support form After the epoxy securing the fiber to the form is cured and hardened, a planar surface extending partially into and along the fiber is established by lapping and polishing the element to a carefully controlled depth The techniques employed and the resulting devices permit coupling between pairs of individual fibers joined in the manner described