Some aspects of the aerodynamics of STOL ports
Wind pressure and cross flow velocity profiles for short takeoff aircraft building roof airports
Blanton, J. N.↗
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Effect of inlet geometry on flow-angle characteristics of miniature total-pressure tubes
Inlet nozzle geometry effects on subsonic flow characteristics of miniature total pressure tubes including pitot tube static and dynamic pressure and flow velocity measurements
Dudzinski, T. J.↗
Diffusion of heavy ions in the solar corona
Heavy ion diffusion in solar corona, emphasizing flow velocity and density
Alloucherie, Y.↗
Microwave methods for cryogenic liquid and slush instrumentation
Microwave systems for cryogenic liquid and slush density and flow velocity measurements
Ellerbruch, D. A.↗
Energy deposition in parallel-plate plasma accelerators
Parallel plate plasma accelerator energy deposition, considering kinetic and thermal modes based on flow velocity, temperature and Mach number measurements
Di Capua, M. S.↗
The calculation of optimal linings for jet engine inlet ducts
Optimal lining impedance for jet engine inlet duct, yielding discrete frequency, flow velocity and geometry on basis of minimum radiated power
Wilkinson, J. P. D.↗
Effect of random fluctuations in pressure gradient on channel flow
Stationary Gaussian Markovian form randomly fluctuating pressure gradient effects on steady incompressible channel flow velocity
Perlmutter, M.↗
Experimental investigation of pressure wave propagation in a pipe
Temporal and spatial flow velocity profiles produced by shock tube generated pressure wave propagation in open-end pipe
Loh, M. J.↗
A model for the acoustic impedance of a perforated plate liner with multiple frequency excitation
A nonlinear resistance model is used in the one-dimensional equations of motion with an arbitrary exciting pressure function. The effects of high amplitude fluid motion, grazing flow, and spectral excitation can be studied together. Sample calculations of acoustic resistances are presented using a high amplitude discrete tone superimposed upon a simulated white noise spectrum. The tone amplitude is varied and its effect is shown both with and without a grazing flow velocity.
Rice, E. J.↗
A study of waves in the earth's bow shock
The perturbation vectors of waves up and downstream from the region of maximum compression in the bow shock were examined on OGO-5 under particularly steady solar wind conditions. The polarization of the upstream waves was RH, circular and of the downstream waves LH, elliptical in the spacecraft frame. By observing that the polarization of the waves remained unchanged as the shock motion swept the wave structure back and forth across the satellite three times in eight minutes, it was found that the waves were not stationary in the shock frame. A study of the methods of determining the shock normal indicates that the normal estimated from a shock model should be superior to one based upon magnetic coplanarity. The propagation vectors of the waves examined did not coincide with the shock model normal, the average magnetic field, or the plasma flow velocity. However, the major axis of the polarization ellipse of the downstream wave was nearly parallel to the upstream propagation vector.
Holzer, R. E.↗
A model for the acoustic impedance of a perforated plate liner with multiple frequency excitation.
An analytical model for the determination of the acoustic impedance of a perforated plate liner is presented. The model allows the calculation of the effect on acoustic impedance of multiple frequency excitation. A nonlinear resistance model is used in the one-dimensional equations of motion with an arbitrary exciting pressure function. The effects of high amplitude fluid motion, grazing flow, and spectral excitation can thus be studied together. Sample calculations of acoustic resistances are presented using a high amplitude discrete tone superimposed upon a simulated white noise spectrum. The tone amplitude is varied and its effect is shown both with and without a grazing flow velocity.
Rice, E. J.↗
Study of waves in the earth's bow shock.
Results of an examination of the perturbation vectors of waves upstream and downstream from the region of maximum compression in the bow shock on Ogo 5 under particularly steady solar-wind conditions. The polarization of the upstream waves was right-hand circular, and that of the downstream waves left-hand elliptical in the spacecraft frame. By observing that the polarization of the waves remained unchanged as the shock motion swept the wave structure back and forth across the satellite three times in eight minutes, it was found that the waves were not stationary in the shock frame. A study of the methods of determining the shock normal indicates that the normal estimated from a shock model should be superior to the normal based on magnetic coplanarity. The propagation vectors of the waves examined did not coincide with the shock-model normal, the average magnetic field, or the plasma-flow velocity. However, the major axis of the polarization ellipse of the downstream wave was nearly parallel to the upstream propagation vector.
Holzer, R. E.↗
Effect of duct shape, Mach number, and lining construction on measured suppressor attenuation and comparison with theory
Noise attenuation was measured for several types of cylindrical suppressors that use a duct lining composed of honeycomb cells covered with a perforated plate. The experimental technique used gave attenuation data that were repeatable and free of noise floors and other sources of error. The suppressor length, the effective acoustic diameter, suppressor shape and flow velocity were varied. The agreement among the attenuation data and two widely used analytical models was generally satisfactory. Changes were also made in the construction of the acoustic lining to measure their effect on attenuation. One of these produced a very broadband muffler.
Olsen, W. A.↗
Design integration and noise studies for jet STOL aircraft. Task 7A: Augmentor wing cruise blowing valveless system. Volume 2: Design exploration
A design integration study program was conducted to determine size and performance parameters of an augmentor wing cruise blowing (valveless) system in a 150-passenger STOL airplane for the purpose of defining size and configuration of static rig, flow duct, and wind tunnel test hardware. The studies encompassed blowing systems powered by low-pressure (single stage) and high-pressure (three and four stage) engine fans. A range of wing aspect ratios, wing thicknesses, and duct flow velocity effects were investigated to establish airplane characteristics which minimize takeoff gross weight while achieving sideline noise requirements for an advanced commercial STOL airplane.
Source record↗
Acoustic radiation from plates excited by flow noise.
Theoretical formulation of noise radiation from thin, rectangular, flexible plates excited by turbulent wall pressure fluctuations. An extensive parametric study including surface roughness and both plate and flow parameters is presented. From the results, presented graphically, it is possible to predict the spectrum of the total radiated power provided that the power spectral density of the wall-pressure fluctuations, the flow velocity, the plate dimensions and the plate modal damping parameters are known. Along with the parametric study, an estimate of the dependence of the noise radiation on plate boundary conditions based on a consideration of the wavenumber-frequency selectivity of the plate is presented. The parametric study is based on the assumption that the wave number/frequency spectrum of the wall-pressure fluctuations can be described by a Fourier transform of a Corcos model of the cross spectral density. The results indicate that at frequencies above the hydrodynamic-coincidence frequency the radiated power is dependent on the low-wave-number spectrum of the excitation. The dependence on the high-wave-number spectrum, however, is limited to a narrow band of frequencies below the hydrodynamic-coincidence frequency.
Aupperle, F. A.↗
High pressure oxygen utilization by NASA.
The conditions of use of oxygen by NASA are severe, since moving liquid oxygen at the rates required by large rocket engines calls for high pressures and high flow velocities. NASA also has requirements for gaseous oxygen systems that operate at pressures above the range of industrial practice. Some of the facts pointing up the need for improved criteria for oxygen handling, and work within NASA aimed at developing them are reviewed. Research on oxygen compatibility at high pressure is described. It is shown that the degradation of mechanical properties, the susceptibility to ignition by various stimuli, and the resistance to burning must be quantitatively defined.
Belles, F. E.↗
The 3 DLE instrument on ATS-5
The performance and operation of the DLE plasma electron counter on board the ATS 5 are described. Two methods of data presentation, microfilm line plots and spectrograms, are discussed along with plasma dynamics, plasma flow velocity, electrostatic charging, and wave-particle interactions.
Deforest, S. E.↗
Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean
The author has identified the following significant results. Release-recovery paths of drift cards released in conjunction with ERTS-1 overflight show that nearshore surface currents along the central and northern California coast flowed southward at an average rate in excess of 10 cm/sec (8.5 km/day) during August and September 1973 (California Current). By the middle of October 1973, the nearshore surface currents had reversed and the dominant flow velocity was northward at an average rate in excess of 20 cm/sec (17 km/ day) (Davidson Current). The August-September data suggested the presence of counterclockwise gyres in Monterey Bay and the Gulf of the Farallones, but by the middle of October, the gyres were no longer evident. Imagery of April 1973 showed well developed plumes of suspended sediment in Monterey Bay from the Salinas River and in the Gulf of the Farallones from San Francisco Bay. ERTS-1 imagery provides an effective means of monitoring timber harvest in the redwood forest along the northern California coast. ERTS-1 imagery also clearly portrays contrasting topographic belts characterized by fluvial erosion and by mass movement. The most visually apparent and most persistent river mouth suspended sediment plumes are associated with those rivers that drain belts of topography that appear to have been eroded primarily by mass movement.
Carlson, P. R.↗