Panel flutter theory applied to aeroelastic stability of flat unloaded plates and cylindrical shells

Panel flutter - A review of the aeroelastic stability of plates and shells

A numerical procedure is developed for determining the relative proportions of selected elements of an aircraft structure, to attain a specified flutter speed with minimum total mass. The procedure is based on a finite-element idealization of the structure. Lagrange multipliers are employed to introduce the conditions for neutral dynamic stability (flutter equations) as dynamic constraints. The resulting system of nonlinear equations is solved by the Newton-Raphson process to determine the masses of the elements of the system. b [B] [C] [K]

Optimization of structures to satisfy flutter requirements.

Operating characteristics of a 60- and 10-cm electric arc-driven shock tube. I - The driver. II - The driven section

This paper describes a test series in the Electric Arc Shock Tube at NASA Ames Research Center with the objective of quantifying shock-layer radiative heating magnitudes for future probe entries in...

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Shock Radiation Tests for Saturn and Uranus Entry Probes

: A method of solution of the laminar boundary layer equations for dissociating and ionizing air in chemical nonequilibrium is formulated for arbitrary pressure gradients and body geometry A nonsimilar, multistrip integral technique is employed in conjunction with previously derived transport and thermodynamic properties for the multicomponent mixture Several numerical examples are carried out for sharp conical bodies (assuming a fully catalytic cold wall) at reentry velocities and altitudes between 115 and 200 kilofeet The results are used to demonstrate a number of salient features of the flow fields; among these are the dominant role of diffusion in counterbalancing the production of dissociated and ionized species, the relative importance of accurate transport properties in the momentum and energy equations (as reflected in the species production), and the persistence of chemical nonequilibrium to relatively low altitudes (below 15 kilofeet) for slender, sharp vehicles at reentry velocities (Author)

Nonequilibrium, nonsimilar solutions of the laminar boundary layer equations (task 3.1. flow-field analyses. rest project),

Review of some exploratory test results for an electrical discharge driver with a conical-shaped arc chamber. The characteristics of the discharge cycle in the conical chamber and the shock tube performance are described, and the obtained results are compared with those reported by Menard (1971).

A conical arc driver for high-energy test facilities.

An investigation is made to establish predictable electric arcs along triggered paths for research purposes, the intended application being the heating of the driver gas of a 1 MJ electrically driven shock tube. Trigger conductors consisting of wires, open tubes, and tubes pressurized with different gases were investigated either on the axis of the arc chamber or spiraled along the chamber walls. Design criteria are presented for successful arc initiation with reproducible voltage-current characteristics. Results are compared with other facilities and several application areas are discussed.

Arc Driver Operation for Either Efficient Energy Transfer or High-Current Generation

Development of Dynamic Discharge Arc Driver with Computer-Aided Circuit Simulation

Image converter camera and astronomical telescope arrangement for photographing metal diaphragm openings in shock tube

A novel use of a telescope to photograph metal diaphragm openings.

Dwell or dark pause measurements of shock tube driver high pressure arc discharge for various gases

Robert E. Dannenberg

Papers

A conical arc driver for high-energy test facilities.

Arc Driver Operation for Either Efficient Energy Transfer or High-Current Generation

Development of Dynamic Discharge Arc Driver with Computer-Aided Circuit Simulation

A novel use of a telescope to photograph metal diaphragm openings.

Dark-pause measurements in a high-pressure arc discharge