Engineering topics

Jones, Robert A.

Publications and source records attributed to Jones, Robert A..

5 records

NASA NTRS1990

Opportunities for improved understanding of supersonic and hypersonic flows

This overview describes some of the diverse applications which are foreseen in the supersonic and hypersonic regime, and points out both the need and the opportunity for improved understanding of the subject. New facilities and experimental test techniques combined with computational fluid dynamics methods are described to illustrate challenging flows over supersonic wings, separated free-shear mixing layers, and in scramjet-airframe integration.

Jones, Robert A.↗

NASA NTRS1987

From earth to orbit in a single stage

The National Aerospace Plane (NASP) program's preliminary analyses indicate that the ability to reach orbit is governed by average thrust/drag, average propulsion efficiency, and the ratio of takeoff fuel weight to total takeoff weight; examinations of each of the governing parameters have in turn pointed to the technology development efforts that must be undertaken for the realization of such a single-stage-to-orbit airbreathing vehicle. The key to the achievement of high thrust/drag, in particular, is the integration of engine intake compression and exhaust expansion functions with the airframe. The portion of the vehicle cross-sectional area thus employed in leading the airstream into the engine inlet should be as close to 100 percent as possible.

Jones, Robert A.↗

NASA NTRS1962

Preliminary Results on Heat Transfer to the Afterbody of the Apollo Reentry Configuration at a Mach Number of 8

Heat-transfer rates on the afterbody of the Apollo reentry configuration have been measured in a low-enthalpy wind tunnel at a Mach number of 8. The data have been presented as the ratio of the measured heat-transfer coefficient on the afterbody to the calculated heat-transfer coefficient at the stagnation point at zero angle of attack. This ratio was found to vary from a low of approximately 0.01 to a maximum of about 0.52 as the angle of attack varied from 0 to 55 deg.

Jones, Robert A.↗

NASA NTRS1961

Heat-Transfer Tests of 20-Millimeter Projectiles at a Mach Number of 5 with an Analysis by Unsteady Scaling Laws to Predict Component Temperature Rises after Firing for Various Free-Flight Conditions

The temperature time history of various components of a 20-millimeter projectile was obtained by transient heating tests in a Mach number 5 blowdown tunnel. An unsteady scaling law is derived and used to predict the temperature time histories after firing in flight at various Mach numbers and altitudes.

Trimpi, Robert L.↗

NASA NTRS1959

An Experimental Study at a Mach Number of 3 of the Effect of Turbulence Level and Sandpaper Type Roughness on Transition on a Flat Plate

An investigation has been conducted at a Mach number of 3 of the effect of turbulence level and sandpaper-type roughness on transition for a flat plate. The Reynolds number varied from 0.8 x 10(exp 6) to 1.8 x 10(exp 6) per inch; the settling-chamber turbulence level varied from 0.7 percent to 35 percent; and the heat transfer between the plate and the stream was negligible. Transition locations were determined by an optical method. This method was indicative of a permanent change in the boundary-layer density distribution rather than the onset of turbulent bursts. Results showed that, when transition was influenced by roughness, it moved in a way similar to its movement on a smooth plate. That is, it gradually approached the roughness location with either an increase in unit Reynolds number or an increase in turbulence level. For roughness submerged in the linear portion of the boundary-layer velocity profile, the square root of the roughness Reynolds number and the ratio of roughness height to boundary-layer displacement thickness gave similar results as parameters for predicting the effects of roughness. A range of each of these parameters which moved transition less than 10 percent was found and this range was a function of turbulence level.

Jones, Robert A.↗