This thesis studies the target identified by analyzed scattering signal which is from active sonar impinged under water. In general, the specular reflected waves and corner waves provide the information of target profile in scattering signal. The resonance scattering waves and surface waves submit the material properties of target by analysis signal. The Rayleigh wave is a candidate for target identified in surface wave analysis. Since then, the theorem focuses on Rayleigh wave propagation on solid sphere and cylinder in this thesis. To analyze the problem of scattering wave, if the normal mode methed is applied to solve it, the character of reflected surface wave can not appear on the solution. So the Sommerfeld-Watson transform(SWT) method is used to solve it. This method can convege the infinite partial-wave series rapidly and the physical property of acoustic wave can be elucidated easily. In experiment, the reduced scale experiment is setup for Rayleigh wave measurement using ultrasonic wave. For Rayleigh wave discussion, the individual profile, sizes and material of target is applied respectively in this experiment. The beam pattern is also measured in the Rayleigh wave filed. The result appears the target identified by analytical Rayleigh wave obviously.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 109-110).

Rayleigh Scattering from neutral nitrogen and argon at room temperature has been studied using a 12 megawatt Q-switched pulse ruby laser. The scattering angle was chosen to be 90 degrees from the incident beam. The relative differential scattering cross-section and the pressure dependence of the scattered signal of the scattering media were determined. Measurements of the absolute differential cross-section of nitrogen and argon were also obtained. I found that the results agree very satisfactorily with the prediction of the theory within experimental error. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

No description available.

Xiao Yi-fei = 瑞利-伯纳德对流中的局域热传导的测量 / 肖毅腓. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 85-89). / Text in English; abstracts in English and Chinese. / Xiao Yi-fei = Ruili-Bonade dui liu zhong de ju yu re chuan dao de ce liang / Xiao Yifei. / Abstract (in Chinese) --- p.i / Abstract (in English) --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.xi / Chapter Chapter 1 --- Theory and Some Physical Picture in Raleigh-Benard convection --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Rayleigh-Benard Convection and its dominated element --- p.3 / Chapter 1.2.1 --- Free convection Equation --- p.3 / Chapter 1.2.2 --- Heat transfer equation in Experiment --- p.6 / Chapter 1.2.3 --- Physical Picture of Plumes --- p.8 / Chapter 1.2.4 --- Large Scale Structure and Plumes --- p.9 / Chapter Chapter 2 --- Experimental Setup and Instrumentation --- p.11 / Chapter 2.1 --- The convection Cell for the experiment --- p.11 / Chapter 2.2 --- Temperature probe and its calibration --- p.14 / Chapter 2.3 --- Principle of Wheatstone electrical Bridge --- p.17 / Chapter 2.4 --- The Principle of Laser Doppler Velocimetry (LDV) --- p.21 / Chapter 2.4.1 --- Features of LDV / Chapter 2.4.2 --- Measurement position in Simultaneous Measurement Velocity and Temperature --- p.25 / Chapter 2.4.3 --- Data analysis of LDV --- p.27 / Chapter Chapter 3 --- Measurement of Local Heat Flux --- p.31 / Chapter 3.1 --- Simultaneous measurement velocity in Different Distance --- p.31 / Chapter 3.2 --- Treatment of Heat Flux Signals --- p.40 / Chapter 3.2.1 --- Sampling Clock of Heat Flux --- p.40 / Chapter 3.2.1 --- Expanding j Relative to Mean wind and Local Fluctuation Term --- p.44 / Chapter 3.2.3 --- "Temperature, Velocity and Heat Flux's Corrections" --- p.46 / Chapter 3.3 --- Conclusions --- p.50 / Chapter Chapter 4 --- Result and Discussion --- p.51 / Chapter 4.1 --- Spatial structure of Heat Flux --- p.51 / Chapter 4.1.1 --- Ra-dependent Spatial Structure for Flow Along the LSC plane --- p.51 / Chapter 4.1.2 --- Ra-dependent Spatial Structure for Flow Perpendicular to the LSC plane --- p.58 / Chapter 4.1.3 --- Comparisons of Jz and Jzfluc --- p.62 / Chapter 4.2 --- Fluctuations of Local Heat Flux --- p.65 / Chapter 4.2.1 --- At Cell Center --- p.65 / Chapter 4.2.2 --- Near Sidewall --- p.70 / Chapter 4.3 --- Conclusions --- p.80 / Chapter Chapter 5 --- Conclusions and Future Work --- p.81 / Chapter 5.1 --- Conclusions --- p.81 / Chapter 5.2 --- Perspective for Further Investigation --- p.84 / Reference --- p.85 / List of Figures / Chapter 1.1 --- Typical temperature profile along z-direction (From lower plate to upper) --- p.7 / Chapter 2.1 --- Sketch of the convection cell for simultaneous measurement temperature and velocity --- p.12 / Chapter 2.2 --- The setup of temperature probe calibration --- p.15 / Chapter 2.3 --- A typical temperature calibrate Resistance vs. Temperature --- p.16 / Chapter 2.4 --- The Wheatstone bridge and the differential amplifier: R0=10.0 kΩ; R1=R2=R3=Rf=5.0 kΩ; Rv is used to balance the bridge --- p.18 / Chapter 2.5 --- Schematic diagram Principle of the LDV --- p.22 / Chapter 2.6 --- Measuring volume of Laser Doppler Velocimetry --- p.24 / Chapter 2.7 --- Velocity (m/s) vs. Transit Time (ms) --- p.28

Jin, Xiaoli = 關於脈衝驅動熱湍流的實驗研究 / 金晓莉. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 83-86). / Text in English; abstracts in English and Chinese. / Jin, Xiaoli = Guan yu mai chong qu dong re tuan liu de shi yan yan jiu / Jin Xiaoli. / Abstract --- p.ii / Acknowledge --- p.iv / Table of Contents --- p.vii / List of Figures --- p.xii / List of Tables --- p.xiii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Rayleigh-Benard convection --- p.1 / Chapter 1.2 --- Turbulence driven by time-dependent forcing --- p.5 / Chapter 1.3 --- Motivation --- p.7 / Chapter 1.4 --- Organization of the thesis --- p.8 / Chapter 2 --- Experimental Setup --- p.10 / Chapter 2.1 --- The Convection cell --- p.10 / Chapter 2.2 --- Heating and Cooling --- p.14 / Chapter 2.3 --- Temperature and voltage measurement --- p.15 / Chapter 2.3.1 --- Temperature probes --- p.16 / Chapter 2.3.2 --- Data acquisition: digital multimeter --- p.17 / Chapter 2.3.3 --- Data acquisition: AC Wheatstone bridge and Lock-in amplifier --- p.18 / Chapter 3 --- Steadily driven thermal turbulence: constant heating --- p.21 / Chapter 3.1 --- Local temperature fluctuations --- p.21 / Chapter 3.2 --- Signatures of plume emissions inside conducting plates --- p.26 / Chapter 3.3 --- Nusselt number --- p.33 / Chapter 3.4 --- Correlation functions and Power spectrums --- p.35 / Chapter 4 --- Kicked turbulence: periodically pulsed heating --- p.38 / Chapter 4.1 --- Periodically pulsed heating power --- p.38 / Chapter 4.2 --- In-plate temperature signals --- p.39 / Chapter 4.3 --- Rayleigh number controlling --- p.42 / Chapter 4.3.1 --- Experimental results --- p.42 / Chapter 4.3.2 --- Theoretical explanation: mean-field theory --- p.47 / Chapter 4.4 --- In-plate temperature fluctuation --- p.55 / Chapter 4.5 --- Correlation functions and power spectra --- p.58 / Chapter 4.6 --- Nusselt number enhancement --- p.62 / Chapter 4.6.1 --- Motivation --- p.62 / Chapter 4.6.2 --- Experiment --- p.64 / Chapter 4.6.3 --- Results --- p.66 / Chapter 4.6.4 --- Discussion --- p.70 / Chapter 5 --- Modulated turbulence: sinusoidal heating --- p.75 / Chapter 5.1 --- Motivation --- p.75 / Chapter 5.2 --- Nusselt number measurement --- p.76 / Chapter 6 --- Conclusion --- p.80 / Chapter 6.1 --- Periodically kicked turbulence --- p.80 / Chapter 6.2 --- Sinusoidally modulated turbulence --- p.81 / Chapter 6.3 --- Future works --- p.82 / Bibliography --- p.82

La microscopie hyperfréquence en champ proche permet de vaincre le critère de Rayleigh grâce à une sonde locale qui alimentée par un signal micro-onde génère des ondes évanescentes confinées à son extrémité. Les limites de résolution ne sont alors plus fixées par la longueur d’onde des signaux hyperfréquences exploités, mais principalement par la géométrie de la sonde. Dans ce type de caractérisation, associant généralement un analyseur de réseaux et une sonde champ proche, la limitation majeure réside dans la faible sensibilité de mesure induite par le contraste d’impédances entre l’analyseur et la sonde. En effet, la grande différence d’impédance entre l’analyseur (50Ω) et les sondes champ proche (quelques k Ω) se traduit par une désadaptation importante qui entrave une bonne qualité de mesure. Dans ce travail de thèse, nous nous proposons donc d’apporter des solutions à cette problématique afin de profiter pleinement des potentialités des techniques de microscopie champ proche hyperfréquence. Dans cet objectif, une méthode interférométrique est alors proposée et formalisée. Nous montrons ainsi que l’exploitation conjointe de méthodes de mesures hyperfréquences, de procédés de microscopie champ proche et de techniques interférométriques doit permettre d’entrevoir des caractérisations à haut pouvoir de résolution spatiale sur une large gamme de fréquences. La démonstration que ces nouveaux outils offrent la possibilité de mesures hyperfréquences vectorielles de type point-à-point, de scanning 1D ou d’imagerie 2D sur des courses centimétriques pour des fréquences allant jusque 20 GHz avec des résolutions spatiales micrométriques est alors faite. En particulier, des applications autour de la caractérisation diélectrique locale sont proposées. Les résultats obtenus montrent que les techniques proposées se situent à l’état de l’art en termes de gamme de fréquence d’opération et de sensibilité de mesure / Near-field microwave microscopy overcomes the Rayleigh criterion thanks to a local probe whitch fed by a microwave signal generates evanescent waves confined at its end. The resolution limits are no longer determined by the wavelength of the microwave signals, but mainly by the probe geometry. In this kind of characterization technique based on the association of a network analyzer and a near-field probe, the main limitation is the poor measurement sensitivity related to the impedance contrast between the analyzer and the probe. Indeed, the large difference between the impedances of the analyzer (50Ω) and near field probes (a few kΩ) results in a significant mismatch hampering good measurements. In this PhD thesis, we provide solutions to tackle this problem in order to take full advantage of the potentialities of near-field microwave microscopy techniques. An interferometric method is then introduced and formalized. We show that the association of microwave measurements, near-field microscopy methods and interferometry techniques allow foreseeing microwave characterizations with high spatial resolution over a broad frequency range. We demonstrate that these new tools offer the possibility of microwave measurements of the type point-to-point, 1D scanning or 2D imaging on centimeter ranges up to 20 GHz with micrometric spatial resolutions. In particular, local dielectric characterization - related applications are proposed. The results obtained show that the proposed techniques are at the state of the art in terms of operating frequency range and measurement sensitivity.

Typescript / 141 leaves : ill., appendix in end pocket / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Experimental determination of the dispersion of Rayleigh waves across Australia has provided information about the earth's crust in this region. This technique is particularly useful in Australia, where in many areas the low level of natural seismicity prohibits the use of more conventional methods of investigation of the crust. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1967

This research studies higher harmonics of Rayleigh surface waves propagating in nickel base superalloys. Rayleigh waves are used because they carry most of the energy and travel along the surface of a specimen where fatigue damage is typically initiated. The energy concentration near the free surface leads to stronger nonlinear effects compared to bulk waves. An ultrasonic piezoelectric transducer together with a plastic wedge is used for the experimental generation of the Rayleigh wave. The detection system consists of a laser heterodyne interferometer. Measurements are performed to detect the fundamental wave as well as the second harmonic. The amplitude ratio is related to the nonlinearity parameter beta which is typically used to describe changes in microstructure and investigate fatigue damage.

There are two coupled objectives for this study of buoyancy-driven turbulence. The first objective is to determine if the development of a Rayleigh-Taylor (RT) mixing layer can be manipulated experimentally by altering the initial condition of the experiment. The second objective is to evaluate the performance of the Besnard, Harlow, and Rauenzahn (BHR) turbulent transport model when initialized with experimentally measured initial conditions. An existing statistically steady water channel facility at Texas A&M University and existing experimental diagnostics developed for this facility have been used to measure the turbulent quantities of buoyancy-driven turbulence. A stationary, bi-planar grid with a high solidity ratio, σ, has been placed immediately downstream of the termination of the splitter plate, perpendicular to the flow direction, to generate a turbulent initial condition. The self-similar growth parameter, α , for the RT mixing layer has been measured using a visualization technique to determine if the initial conditions affect the development of the RT mixing layer. The self-similar growth parameter, α , decreased from a value of 0.072 ± 0.0003 with the fine grid to values of 0.063 ± 0.0003 and 0.060 ± 0.0003 with the medium and coarse grids, respectively. With the results from the first objective, a unique opportunity arose to evaluate the performance of the variable density, RANS-type, BHR turbulent transport model. Measurements of velocity statistics necessary to initialize the model accurately have been obtained using particle image velocimetry (PIV). The performance of the BHR model was evaluated through comparison of the experimentally measured and BHR modeled self-similar growth parameter, α , from the penetration height of the bubbles/spikes and the self-similar growth parameter, K α , of the turbulent kinetic energy at the centerline of the low Atwood RT driven turbulent mixing layer. When initialized with the experimentally measured initial conditions, the BHR model did agree with the experimental measurements of the penetration height growth parameter, α , as well as the centerline turbulent kinetic energy growth parameter, K α , in the self-similar portion of the flow.