On the use of slowness diagrams to represent wave reflections
Plane wave reflection decay rate representation by slowness diagrams
Crandall, S. H.↗
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Results for “WAVE REFLECTION”
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Reflected-wave maser
Reflected wave maser amplifier has significantly greater bandwidth than conventional maser amplifiers. Unit needs no retuning to receive wide range of frequencies.
Clauss, R. C.↗
Alfven wave reflection and heating in coronal holes - Theory and observation
We present evidence for significant reflection of Alfven waves in an isothermal, hydrostatic model corona and that heating in coronal holes is provided by Alfven waves. For Alfven waves with periods of 5 min, upward propagating waves are reflected if the temperature is less than 10 exp 6 K, but escape into the solar wind if the temperature is greater than 10 exp 6 K. This sensitive temperature dependence may provide the self-limiting mechanism that has been suspected to exist because the reflected waves result in heating which raises the temperature which, in turn, decreases the reflection. The reflection occurs mostly inside of about 6 solar radii, depending on temperature, wave period, and magnetic field strength and geometry. The importance of this process has often been overlooked due to a poor choice of coronal Alfven speed and temperature. SOHO is well-suited to measure whether the required properties for reflection exist. Solar Probe, however, is the only definitive experiment to show if the waves actually exist to the degree necessary.
Suess, S. T.↗
Analysis of an axial compressor blade vibration based on wave reflection theory
The paper describes application of the theory of wave reflection in turbomachines to rotor blade vibrations measured in an axial compressor stage. The blade vibrations analyzed could not be predicted using various flutter prediction techniques. The wave reflection theory, first advanced in 1966, is expanded, and more general equations for the rotor blade excitation frequencies are derived. The results of the analysis indicate that all examined rotor blade vibrations can be explained by forced excitations caused by reflecting waves (pressure pulses). Wave reflections between the rotor blades and both the upstream and downstream stator vanes had to be considered.
Owczarek, J. A.↗
Verification of a simple relationship for shock-wave reflection in a relaxing gas
Shock-wave reflection study in a relaxing gas using pressure measurement techniques and aimed at verifying the relationship recently described by Hanson (1971) for such a shock wave reflection. The obtained results show good agreement with theory, the maximum discrepancy being about equal to the experimental uncertainty.
Hanson, R. K.↗
INFLUENCE OF WAVE REFLECTIONS ON THE DEVELOPMENT OF DETONATION
Influence of wave reflections on the development of detonation
REFLECTION↗
An atlas of total outgoing long-wave radiation and of short-wave reflectances from Nimbus II observations
Atlas of total outgoing long-wave radiation and of short-wave reflectances from Nimbus II
SHORT WAVE RADIATION↗
A 32-GHz reflected-wave maser amplifier with wide instantaneous bandwidth
An eight stage, 32 GHz reflected wave ruby maser was built. The maser operates in a 3 watt closed cycle refrigerator at 4.5 K and is capable of 21 dB of net gain with an instantaneous bandwidth of 400 MHz. The input noise temperature referred to the room temperature flange is approximately 21 K.
Shell, J.↗
Onset and Forecast of the 1994-1995 El Nino Event: Equatorial Rossby Wave Reflection Evidenced by TOPEX/POSEIDON
We found evidence in TOPEX/POSEIDON sea level data that equatorial first meridionsl mode Rossby waves reflected at the Pacific western boundary into Kelvin waves during the January-july 1994 period prior to the 1994-1995 El Nino event.
ocean atmosphere modeling el nino rossby wave tope↗
An experimental and analytical investigation of shock-wave reflection in a chemically relaxing gas
Experimental and analytical study of normal reflection of shock wave from shock tube end wall in relaxing diatomic gas
Hanson, R. K.↗
(abstract) Role of Long Equatorial Wave Reflection in the Low-Frequency Variability Observed During the TOPEX/POSEIDON Period: Data Analysis and Coupled Model Study
The analysis of TOPEX/POSEIDON sea level and ERS-1 zonal wind stress data gives evidence that first mode meridonal long Rossby waves fully reflected into Kelvin waves at the equatorial western Pacific boundary at different periods including the January-June 1994 period. The evolution of the conditions (zonal wind stress, sea surface temperature and sea level anomalies) in the central Pacific suggests that this reflection may have played a role in the reversal of cold to warm anomalies observed in the central Pacific in June-July 1994. To investigate the actual role of reflected Kelvin waves observed by TOPEX/POSEIDON, a simple ocean-atmosphere coupled model is designed. Starting from these initial conditions, several simulations are run for testing the role western bundary reflection evidenced in TOPEX/POSEIDON data. Coupled mechanisms are suggested to explain the low-frequency variability observed during this period.
Rossby waves Kelvin waves zonal wind stress TOPEX/↗
Multiple Alfven wave reflections excited by Io Origin of the Jovian decametric arcs
The recent Voyager radio astronomy measurements near Jupiter show that the Jovian decametric radiation consists of numerous discrete features called decametric arcs which are observed at all Jovian longitudes. It is generally believed that these arcs are produced by an interaction of Io with the Jovian magnetosphere. In this paper we propose that the large number of decametric arcs is caused by multiple reflections of a standing Alfven wave current system excited by Io. Estimates of the reflection coefficient at the ionosphere and other damping processes show that a large number of reflections can occur, with the Alfven wave current system possibly extending completely around Jupiter. This source geometry can account for a number of otherwise puzzling characteristics of the Jovian decametric radiations,
Gurnett, D. A.↗
Analysis of the effect on combustor noise measurements of acoustic waves reflected by the turbine and combustor inlet
Spectral analyses of static pressure fluctuations measured in turbine engine combustors at low engine speed show good agreement with theory. At idle speed the high pressure turbine is unchoked. Above idle speed the turbine chokes and a significant change in the shape of the measured combustor pressure spectrum is observed. A simplified theoretical model of the acoustic pressure generated in the combustor due to the turbulence-flame front interaction did not account for acoustic waves reflected from the turbine. By retaining this simplified combustion noise source model and adding a partial reflecting plane at the turbine and combustor inlet, a simple theoretical model was developed that reproduces the undulations in the combustor fluctuating pressure spectra. Plots of the theoretical combustor fluctuating pressure spectra are compared to the measured pressure spectra obtained from the CF6-50 turbofan engine over a range of engine operating speeds. The simplified combustion noise theory when modified by a simple turbine reflecting plane adequately accounts for the changes in measured combustor pressure spectra. It is further concluded that the shape of the pressure spectra downstream of the turbine, neglecting noise generated by the turbine itself, will be the combustion noise spectra unchanged except for the level reduction due to the energy blocked by the turbine.
Huff, R. G.↗
Analysis of the effect on combustor noise measurements of acoustic waves reflected by the turbine and combustor inlet
Spectral analyses of static pressure fluctuations measured in turbine engine combustors at low engine speed show good agreement with theory. At idle speed the high pressure turbine is unchoked. Above idle speed the turbine chokes and a significant change in the shape of the measured combustor pressure spectrum is observed. A simplified theoretical model of the acoustic pressure generated in the combustor due to the turbulence-flame front interaction did not account for acoustic waves reflected from the turbine. By retaining this simplified combustion noise source model and adding a partial reflecting plane at the turbine and combustor inlet, a simple theoretical model was developed that reproduces the undulations in the combustor fluctuating pressure spectra. Plots of the theoretical combustor fluctuating pressure spectra are compared to the measured pressure spectra obtained from the CF6-50 turbofan engine over a range of engine operating speeds. The simplified combustion noise theory when modified by a simple turbine reflecting plane adequately accounts for the changes in measured combustor pressure spectra. It is further concluded that the shape of the pressure spectra downstream of the turbine, neglecting noise generated by the turbine itself, will be the combustion noise spectra unchanged except for the level reduction due to the energy blocked by the turbine.
Huff, R. G.↗
Magnetic confinement, Alfven wave reflection, and the origins of X-ray and mass-loss 'dividing lines' for late-type giants and supergiants
A simple qualitative model for the origin of the coronal and mass-loss dividing lines separating late-type giants and supergiants with and without hot, X-ray-emitting corona, and with and without significant mass loss is discussed. The basic physical effects considered are the necessity of magnetic confinement for hot coronal material on the surface of such stars and the large reflection efficiency for Alfven waves in cool exponential atmospheres. The model assumes that the magnetic field geometry of these stars changes across the observed 'dividing lines' from being mostly closed on the high effective temperature side to being mostly open on the low effective temperature side.
Rosner, R.↗
Experimental study of shock-wave reflection from a thermally accommodating wall.
Shock-tube experiments have been conducted to study the nonequilibrium gas-surface interaction which occurs when a thick shock wave in argon reflects from a coplanar, heat-conducting wall. Fast-response instrumentation was used to monitor variations in temperature and normal stress on the surface of the shock-tube end wall during and immediately following reflection of the incident shock wave. The laboratory observations are compared with computer predictions obtained by Deiwert using the direct-simulation Monte Carlo method, and excellent agreement is obtained when a suitable average thermal accommodation coefficient is chosen for the wall surface.
Hanson, R. K.↗
Long Equatorial Wave Reflection. Comparison of TOPEX/POSEIDON Data and an OGCM Simulation
The accuracy of TOPEX/Poseidon sea-level data allows investigation of some theoretical mechanisms suggested to be involved in the El Nino/Southern Oscillation phenomenon. The delayed action oscillator scenario using the TOPEX/Poseidon data is tested. Sea-level data is projected onto long equatorial Kelvin and first Rossby waves. Other simulations, models, projections, and discrepancies are discussed.
oceanography remote sensing satellite observation ↗
Reflected-wave maser
A number of traveling-wave, slow-wave maser structures, containing active maser material but absent the typical ferrite isolators, are immersed in a nonuniform magnetic field. The microwave signal to be amplified is inserted at a circulator which directs the signal to a slow-wave structure. The signal travels through the slow-wave structure, being amplified according to the distance traveled. The end of the slow-wave structure farthest from the circulator is arranged to be a point of maximum reflection of the signal traveling through the slow-wave structure. As a consequence, the signal to be amplified traverses the slow-wave structure again, in the opposite direction (towards the circulator) experiencing amplification equivalent to that achieved by a conventional traveling-wave maser having twice the length. The circulator directs the amplified signal to following like stages of amplification. Isolators are used in between stages to prevent signals from traveling in the wrong direction, between the stages. Reduced signal loss is experienced at each stage. The high gain produced by each slow-wave structure is reduced to a moderate value by use of a nonuniform magnetic field which also broadens the line width of the maser material. The resulting bandwidth can be exceptionally wide. Cascaded stages provide high gain, exceptionally wide bandwith and very low noise temperature.
Clauss, R. C.↗