Engineering topics

Leighty, B. D.

Publications and source records attributed to Leighty, B. D..

4 records

NASA NTRS1988

Two-mirrored galvanometer laser light sheet generator

Light sheets generated with either laser or noncoherent sources have found widespread application to flow visualization. Previous light sheet generating systems were usually dedicated to a specific viewing geometry. The technique with the most flexibility is the galvanometer mirror based laser light sheet system. A two-mirrored system was designed and developed to provide flexibility and adaptability to a wide range of applications. The design includes the capability to control the size and location of the laser light sheet in real time, to generate horizontal or vertical sheets, to sweep the sheet repeatedly through a volume, to generate multiple sheets with controllable separation and to rotate single or multiple laser light sheets. The system is capable of producing up to 12 sheets of laser light at an angular divergence of + or - 20 degrees. Maximum scan rate of any one line is 500 Hertz. This system has proven to be uniquely versatile and a patent has been applied for.

Leighty, B. D.↗

NASA NTRS1986

ROM-Based Plan-Position-Indicator Sweep Driver

Circuit produces PPI display on conventional X-Y oscilloscope. Circuit requires three inputs. First is once-per-scan pulse to synchronize display to north, relative heading, or another reference direction. Second is once-per-degree-of-rotation pulse to advance sweep rotation. Third input is normal sweep ramp. Duration of ramp corresponds to maximum displayed range. Changing ramp duration, while holding its peak amplitude constant, changes maximum displayed range. Conventional methods to accomplish this task use mechanically-driven deflection coils or mechanically-driven sine and cosine potentiometers, requiring mechanical preventive maintenance plus dedicated display indicator. New method displays radar sweep on any conventional storage oscilloscope.

Franke, J. M.↗

NASA NTRS1985

Power Supply For 25-Watt Arc Lamp

Dual-voltage circuitry both strikes and maintains arc. New power supply designed (and several units already in use) that replaces relay/choke combination with solid-state starter. New power supply consists of two main sections. First section (low voltage power supply section) is 84-volt directcurrent supply. Second section (high-voltage starter circuit) is CockroftWalton voltage multiplier. Used as light sources for schlieren, shadowgraph, and other flow-visualization techniques.

Leighty, B. D.↗

NASA NTRS1983

Moire deflectometry with deferred analysis

A simplified version of moire deflectometry for flow visualization is presented. The modification comprises replacement of the second grating, the ground glass screen, and the camera with a plate film holder to obtain a shadow picture. Postanalysis proceeds by placing a grid transparency of the same periodicity of the remaining glass grating on the negative for projection viewing. The rotational angle between the grating and the plate alters the moire fringe periodicity. Use of the method in studying flows is predicted to reveal weak density gradient areas and shocks.

Rhodes, D. B.↗