Engineering topics
Publications and source records attributed to Dayman, B., Jr..
CARYAW predicts effects of wind on aerodynamic resistance of vehicles. Determines effect of winds on fuel consumption and determines effects of vehicle speed on fuel consumption for wide variety of wind conditions.
The degree to which it is possible to attenuate the effects of pressure pulses on the passengers in trains entering tunnels by modifying the normally abrupt portal of a constant-diameter single track tunnel was investigated. Although the suggested modifications to the tunnel entrance portal may not appreciably decrease the magnitude of the pressure rise, they are very effective in reducing the discomfort to the human ear by substantially decreasing the rate of pressure rise to that which the normal ear can accommodate. Qualitative comparison was made of this portal modification approach with other approaches: decreasing the train speed or sealing the cars. The optimum approach, which is dependent upon the conditions and requirements of each particular rail system, is likely to be the portal modification one for a rapid rail mass transit system.
The feasibility of less spacious, less costly underground rail mass transit system designs is studied. The major cost saving expected from alternative tunnel designs results from using precast concrete segment liners in place of steel. The saying expected for a two-foot decrease in the diameter of twin, single track tunnels is about two million dollars per route mile from 13 million dollars for precast concrete segment liners (a saving of about 16%). The cost per route-mile of a double track tunnel appears to be 15 to 25% higher than for the twin, single track tunnels. The effective cost saving expected from stations with four-car train capability instead of the usual eight-car trains is nearly 25% or seven million dollars per route mile. The saving in station costs can be obtained while improving service to the user (lower transit time and less waiting for trains) up to a capacity of 36,000 riders per hour in each direction.
A simplified theoretical model for a vehicle traveling through an unvented tube under equilibrium incompressible conditions was used to guide the test program, reduce the data, and determine the self-consistency of the results. The results were then used to establish values for the arbitrary coefficients in the theoretical model. Substantial progress was made in understanding the aerodynamic characteristics of vehicles traveling in tubes as exemplified by the good agreement of the theoretical model predictions with the experimental data throughout the Reynolds number range (three orders of magnitude, up to that for an actual full-scale system) and the many geometric variables tested.
The present work discusses in general terms the various kinds of ground facilities, in particular, wind tunnels, which support aerodynamic testing. Since not all flight parameters can be simulated simultaneously, an important problem consists in matching parameters. It is pointed out that there is a lack of wind tunnels for a complete Reynolds-number simulation. Using a computer to simulate flow fields can result in considerable reduction of wind-tunnel hours required to develop a given flight vehicle.
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Comparative sting supported and free flight tests in hypersonic wind tunnel on modified Apollo launch configuration
Test facilities and procedures for obtaining aerodynamic data required for studying vehicle-in- tube transportation systems
Forebody shape effects on drogue drag tested for various forebody-drogue configurations in supersonic flow
Forebody shape effects on drogue drag tested for various forebody-drogue configurations in supersonic flow
Free flight techniques adapted for high speed wind tunnel testing applications
Wind tunnel free flight testing technique to obtain data on hypersonic viscous effects on slender cones
Atmospheric flight mechanics studies using free flight testing in conventional wind tunnel
Dynamic stability of slender cones subjected to high oscillation amplitude - measurement in wind tunnels by free flight techniques
Support-wire wake interference studies show that side mounts or wires to support models lead to incorrect base flow conditions
Boundary layer thickness on curved walls of 20-in supersonic wind tunnel two-dimensional nozzle
Pitch damping at large angles of oscillation for proposed mars atmosphere-entry vehicles - wind tunnel test methods
Reentry vehicle shape effects on the accuracy and angle-of-attack amplitude and wind tunnel methods for measuring pitch damping