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Journal articles on the topic 'Wave reflections'

Author: Grafiati

Published: 9 March 2023

Last updated: 31 July 2025

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1

Allsop, N. W. H., and S. S. L. Hettiarachchi. "REFLECTIONS FROM COASTAL STRUCTURES." Coastal Engineering Proceedings 1, no. 21 (1988): 58. http://dx.doi.org/10.9753/icce.v21.58.

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Wave reflections at and within a coastal harbour may make a significant contribution to wave disturbance in the harbour. Reflected waves may lead to danger to vessels navigating close to structures, and may reduce the availability of berths within the harbour. Wave reflections may also increase local scour or general reduction in sea bed levels. In the design of breakwaters, sea walls, and coastal revetments, it is therefore important to estimate and compare the reflection performance of alternative structure types. In the use of numerical models of wave motion within harbours, it is essential

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2

Berger, D. S., J. K. Li, W. K. Laskey, and A. Noordergraaf. "Repeated reflection of waves in the systemic arterial system." American Journal of Physiology-Heart and Circulatory Physiology 264, no. 1 (1993): H269—H281. http://dx.doi.org/10.1152/ajpheart.1993.264.1.h269.

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Traditional analysis of pulse-wave propagation and reflection in the arterial system treats measured pressure and flow waves as the sum of a single forward wave (traveling away from the heart) and a single backward wave (traveling toward the heart). The purpose of this study was to develop a more general wave reflection theory that allows repeated reflection of these waves. The arterial system was modeled as a uniform viscoelastic tube terminating in a complex load with reflections occurring at the tube load interface and the heart tube interface. The resulting framework considers the forward

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3

Hametner, Bernhard, Hannah Kastinger, and Siegfried Wassertheurer. "Simulating re-reflections of arterial pressure waves at the aortic valve using difference equations." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 11 (2020): 1243–52. http://dx.doi.org/10.1177/0954411920942704.

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Re-reflections of arterial pressure waves at the aortic valve and their influence on aortic wave shape are only poorly understood so far. Therefore, the aim of this work is to establish a model enabling the simulation of re-reflection and to test its properties. A mathematical difference equation model is used for the simulations. In this model, the aortic blood pressure is split into its forward and backward components which are calculated separately. The respective equations include reflection percentages representing reflections throughout the arterial system and a reflection coefficient at

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Vanden Eynden, Frederic, Bachar El-Oumeiri, Thierry Bové, Guido Van Nooten, and Patrick Segers. "Proximal pressure reducing effect of wave reflection in the pulmonary circulation disappear in obstructive disease: insight from a rabbit model." American Journal of Physiology-Heart and Circulatory Physiology 316, no. 5 (2019): H992—H1004. http://dx.doi.org/10.1152/ajpheart.00635.2018.

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Locating the site of increased resistance within the vascular tree in pulmonary arterial hypertension could assist in both patient diagnosis and tailoring treatment. Wave intensity analysis (WIA) is a wave analysis method that may be capable of localizing the major site of reflection within a vascular system. We investigated the contribution of WIA to the analysis of the pulmonary circulation in a rabbit model with animals subjected to variable occlusive pulmonary disease. Animals were embolized with different sized microspheres for 6 wk ( n = 10) or underwent pulmonary artery (PA) ligation fo

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5

Modra, Ben, Dan Howe, Anthony Folan, and Kate McLean. "CHANNEL CONCENTRATION AND REFLECTIONS FROM DREDGE CHANNELS." Coastal Engineering Proceedings, no. 36v (December 28, 2020): 25. http://dx.doi.org/10.9753/icce.v36v.management.25.

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Wave reflections from dredge channels are an important consideration for coastal infrastructure. A physical model study of a proposed development for the Port of Townsville demonstrated that channel reflection, and the relatively poorly understood channel concentration are significant processes that need to be considered in coastal developments. The study showed that channel reflection and channel concentration can significantly transform the local waves, resulting in complex multidirectional wave fields and higher design wave conditions.Recorded Presentation from the vICCE (YouTube Link): htt

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Pan, Yue, Xiao He, Hao Chen, and Xiuming Wang. "Reflection signals and wellbore scattering waves in acoustic logging while drilling." Journal of Geophysics and Engineering 17, no. 3 (2020): 552–61. http://dx.doi.org/10.1093/jge/gxaa014.

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Abstract In sonic logging while drilling (LWD), it is difficult to extract reflection signals for the goal of geo-steering as the wave fields are so complicated. It is important to analyse the reflection and scattering effects based on the synthetic acoustic signals of the real LWD models, while considering the medium discontinuity at the end of the borehole. We numerically investigate the acoustic LWD responses to reflective boundaries out of the borehole. To simulate the received signals, the 3D finite difference in time domain method is implemented. Mode conversions between the collar and t

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7

Hametner, Bernhard, Hannah Kastinger, and Siegfried Wassertheurer. "P138 Modelling and Simulation of Pressure Re-reflections at the Aortic Valve Using Difference Equations." Artery Research 25, S1 (2019): S176. http://dx.doi.org/10.2991/artres.k-191224.161.

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Abstract Introduction The concept of re-reflections of blood pressure waves at the heart has been neglected in most models and is only poorly understood so far. Therefore, the aim of this work was to develop a simple mathematical model which is capable to represent the effects of wave travel, wave reflection as well as re-reflection at the aortic valve. Methods A mathematical model based on difference equations has been developed. The equation for the backward travelling pressure waves includes several terms, where the forward pressure is multiplied by a specific reflection coefficient and is

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8

van der Baan, Mirko, and Dirk Smit. "Amplitude analysis of isotropic P-wave reflections." GEOPHYSICS 71, no. 6 (2006): C93—C103. http://dx.doi.org/10.1190/1.2335877.

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The analysis of amplitude variation with offset (AVO) of seismic reflections is a very popular tool for detecting gas sands. It is assumed in AVO, however, that plane-wave reflection coefficients can be used directly to analyze amplitudes measured in the time-offset domain. This is not true for near-critical angles of reflection. Plane-wave reflection coefficients incorporate the contribution of the head wave. A plane-wave decomposition such as a proper [Formula: see text] transform must be applied to the seismic data for accurate analysis of reflection coefficients near critical angles. Ampli

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9

Zhu, Jianlin. "A transparent boundary technique for numerical modeling of elastic waves." GEOPHYSICS 64, no. 3 (1999): 963–66. http://dx.doi.org/10.1190/1.1444604.

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In numerical modeling of wave motions, strong reflections from artificial model boundaries may contaminate or mask true reflections from the interior model interfaces. Hence, developing a kind of exterior model boundary transparent to the outgoing waves is of critical importance. Among proposed solutions, e.g., Smith (1974), Kausel and Tassoulas (1981), and Higdon (1991), the most widely used may be the Clayton and Engquist (1977) method of absorbing boundary conditions, based on paraxial approximations for acoustic and elastic‐wave equations. However, absorbing boundary conditions make the re

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10

Vasilev, Eugene I., Tov Elperin, and Gabi Ben-Dor. "Reconsideration of the So-Called von Neumann Paradox in the Reflection of a Shock Wave over a Wedge." Materials Science Forum 566 (November 2007): 1–8. http://dx.doi.org/10.4028/www.scientific.net/msf.566.1.

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Numerous experimental investigations on the reflection of plane shock waves over straight wedges indicated that there is a domain, frequently referred to as the weak shock wave domain, inside which the resulted wave configurations resemble the wave configuration of a Mach reflection although the classical three-shock theory does not provide an analytical solution. This paradox is known in the literature as the von Neumann paradox. While numerically investigating this paradox Colella & Henderson [1] suggested that the observed reflections were not Mach reflections but another reflection, in

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Westerhof, Berend, and Nico Westerhof. "P137 Reflections Revisited: Reinterpretation Required." Artery Research 25, S1 (2019): S175. http://dx.doi.org/10.2991/artres.k-191224.160.

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Abstract Introduction Pressure waveshape derived parameters such as the augmentation index are related to unfavourable cardiovascular events [1]. Wave reflections determine wave shape [2], however, several findings seem to contradict the current views. Current view. The arterial system can be modelled by a tube with a reflection site at the end: the heart sets up waves propagating down the system, reflecting at the end and returning to the heart after twice the travel time, i.e. aortic length over Pulse Wave Velocity (PWV).Data. Return time of the reflected wave is not inversely proportional t

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12

Rendleman, C. A., and F. K. Levin. "Reflection maxima for reflections from single interfaces." GEOPHYSICS 53, no. 2 (1988): 271–75. http://dx.doi.org/10.1190/1.1442462.

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At a workshop on refraction and wide‐angle reflections, Hilterman (1985) pointed out that, in contrast to the plane‐wave case, when there is a point source, a P-wave reflected from a plane interface attains its maximum amplitude at an offset greater than that corresponding to the critical angle (Figure 1). The same conclusion had been drawn earlier by Červený (1967). However, neither Červený’s results, which were based on very complicated mathematical expressions derived by Brekhovskikh (1960), nor Hilterman’s computer‐generated data shed light on the physics implied by the shifted maximum.

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Cahill, Lindsay S., Yu-Qing Zhou, Johnathan Hoggarth, et al. "Placental vascular abnormalities in the mouse alter umbilical artery wave reflections." American Journal of Physiology-Heart and Circulatory Physiology 316, no. 3 (2019): H664—H672. http://dx.doi.org/10.1152/ajpheart.00733.2018.

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Current methods to detect placental vascular pathologies that monitor Doppler ultrasound changes in umbilical artery (UA) pulsatility have only moderate diagnostic utility, particularly in late gestation. In fetal mice, we recently demonstrated that reflected pressure waves propagate counter to the direction of flow in the UA and proposed the measurement of these reflections as a means to detect abnormalities in the placental circulation. In the present study, we used this approach in combination with microcomputed tomography to investigate the relationship between altered placental vascular a

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Chabyshova, Elmira, and Gennady Goloshubin. "Seismic modeling of low-frequency “shadows” beneath gas reservoirs." GEOPHYSICS 79, no. 6 (2014): D417—D423. http://dx.doi.org/10.1190/geo2013-0379.1.

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P-wave amplitude anomalies below reservoir zones can be used as hydrocarbon markers. Some of those anomalies are considerably delayed relatively to the reflections from the reservoir zone. High P-wave attenuation and velocity dispersion of the observed P-waves cannot justify such delays. The hypothesis that these amplitude anomalies are caused by wave propagation through a layered permeable gaseous reservoir is evaluated. The wave propagation through highly interbedded reservoirs suggest an anomalous amount of mode conversions between fast and slow P-waves. The converted P-waves, which propaga

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15

Tiedeman, Simon Alexander, William Allsop, Viviana Russo, and Andy Brown. "A DEMOUNTABLE WAVE ABSORBER FOR WAVE FLUMES AND BASINS." Coastal Engineering Proceedings 1, no. 33 (2012): 37. http://dx.doi.org/10.9753/icce.v33.waves.37.

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Passive wave absorption is an integral component of the physical modeling environment, used to minimise unwanted reflections of wave energy that compromise test results. This paper reviews data for methods of passive absorbers and then extends this knowledge through the design and implementation of a device that can be removed from the working water surface. The modeling tests that were carried out in this paper demonstrate that a parabolic spending beach can perform by absorbing waves with coefficients of reflection Cr(energy) significantly

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16

Skopintseva, Lyubov, Milana Ayzenberg, Martin Landrø, Tatyana Nefedkina, and Arkady M. Aizenberg. "Long-offset AVO inversion of PP reflections from plane interfaces using effective reflection coefficients." GEOPHYSICS 76, no. 6 (2011): C65—C79. http://dx.doi.org/10.1190/geo2010-0079.1.

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A conventional amplitude variation with offset (AVO) inversion is based on geometrical seismics which exploit plane-wave reflection coefficients to describe the reflection phenomenon. Widely exploited linearizations of plane-wave coefficients are mostly valid at pre-critical offsets for media with almost flat and weak-contrast interfaces. Existing linearizations do not account for the seismic frequency range by ignoring the frequency content of the wavelet, which is a strong assumption. Plane-wave reflection coefficients do not fully describe the reflection of seismic waves at near-critical an

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17

Kobler, H. "Arterial wave reflections." Hypertension 22, no. 2 (1993): 268. http://dx.doi.org/10.1161/01.hyp.22.2.268.

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18

Ben-Dor, G., O. Igra, and L. Wang. "Shock Wave Reflections in Dust-Gas Suspensions." Journal of Fluids Engineering 123, no. 1 (2000): 145–53. http://dx.doi.org/10.1115/1.1331558.

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The reflection of planar shock waves from straight wedges in dust-gas suspensions is investigated numerically. The GRP shock capturing scheme and the MacCormac scheme are applied to solve the governing equations of the gaseous and solid phases, respectively. These two schemes have a second-order accuracy both in time and space. It is shown that the presence of the dust significantly affects the shock-wave-reflection-induced flow field. The incident shock wave attenuates and hence unlike the shock wave reflection phenomenon in a pure gas, the flow field in the present case is not pseudo steady.

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Zhu, Xinfa, та George A. McMechan. "Amplitude and phase versus angle for elastic wide-angle reflections in the τ‐p domain". GEOPHYSICS 80, № 1 (2015): N1—N9. http://dx.doi.org/10.1190/geo2013-0191.1.

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Near- and postcritical spherical-wave reflections contain amplitude and phase variations with incident angle that are not predicted by plane-wave solutions. However, if a spherical wavefield is decomposed into plane waves by a time-intercept-slowness ([Formula: see text]) transform, then plane-wave reflection coefficients (the Zoeppritz) can be used as the basis of amplitude/phase versus angle analysis. The spherical-wave effects on reflection coefficients near the critical angle (in the time-offset domain) were decomposed by [Formula: see text] transformation into plane waves. Kinematic ray t

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20

Feng, Zongcai, and Lianjie Huang. "Quasielastic least-squares reverse time migration of PS reflections." GEOPHYSICS 87, no. 3 (2022): S105—S116. http://dx.doi.org/10.1190/geo2021-0109.1.

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Conventional analysis of amplitude variation with offset for elastic PS reflections is based on analytical reflection coefficients in a layered medium, and wave-equation-based PS migration is mainly used to produce a structural image. To overcome this problem, we have developed a least-squares reverse time migration (LSRTM) method for elastic PS reflections based on a quasielastic wave equation. The quasielastic wave equation can accurately model PS reflections with elastic amplitudes under the first-order Born approximation. Our LSRTM method inverts for perturbations of the S-wave velocity an

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21

Ren, Zhiming, Qianzong Bao, and Bingluo Gu. "Joint wave-equation traveltime inversion of diving/direct and reflected waves for P- and S-wave velocity macromodel building." GEOPHYSICS 86, no. 4 (2021): R603—R621. http://dx.doi.org/10.1190/geo2020-0762.1.

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Full-waveform inversion (FWI) suffers from the local minima problem and requires a sufficiently accurate starting model to converge to the correct solution. Wave-equation traveltime inversion (WETI) is an effective tool to retrieve the long-wavelength components of the velocity model. We have developed a joint diving/direct and reflected wave WETI (JDRWETI) method to build P- and S-wave velocity macromodels. We estimate the traveltime shifts of seismic events (diving/direct waves and PP- and PS-reflections) through the dynamic warping scheme and construct a misfit function using the time shift

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22

Chertova, N. B., and Yu V. Grinyaev. "Reflection of elastic waves at the boundary with the specified stresses." Izvestiya vysshikh uchebnykh zavedenii. Fizika, no. 5 (2021): 52–59. http://dx.doi.org/10.17223/00213411/64/5/52.

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The problem of elastic waves reflection at the boundary at given constant stresses is considered. Provided that the reflection laws are fulfilled, analytical expressions are obtained for the reflection coefficients of longitudinal and transverse waves, which allow us to determine the deformations amplitudes at the boundary. The dependences of the reflections coefficients and strain components at the boundary on the angle of incidence of the wave are calculated at nonzero values of normal and tangential stresses at the boundary and the specified wave parameters. The obtained results are analyze

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23

Jeng, Yih. "Shallow seismic investigation of a site with poor reflection quality." GEOPHYSICS 60, no. 6 (1995): 1715–26. http://dx.doi.org/10.1190/1.1443904.

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A shallow seismic reflection experiment was performed on a construction site to determine the feasibility of using reflection seismology to investigate the shallow structure in a weathered sand‐gravel interlayered zone that was known to be a poor transmission of high‐frequency seismic energy. Field‐recording parameters were designed to fit the limited space of the urban construction survey area. A 7 kg sledgehammer was used to generate P‐waves and SH‐waves. Single 100 Hz geophones were deployed at 1.0 m/0.5 m group intervals, and 200/100-Hz low‐cut filters were applied prior to A to D conversi

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Syme, Douglas A., A. Kurt Gamperl, Marvin H. Braun, and David R. Jones. "Wave reflection effects in the central circulation of American alligators (Alligator mississippiensis): what the heart sees." American Journal of Physiology-Heart and Circulatory Physiology 291, no. 4 (2006): H1670—H1678. http://dx.doi.org/10.1152/ajpheart.00097.2006.

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A large central compliance is thought to dominate the hemodynamics of all vertebrates except birds and mammals. Yet large crocodilians may adumbrate the avian and mammalian condition and set the stage for significant wave transmission (reflection) effects, with potentially detrimental impacts on cardiac performance. To investigate whether crocodilians exhibit wave reflection effects, pressures and flows were recorded from the right aorta, carotid artery, and femoral artery of six adult, anesthetized American alligators ( Alligator mississippiensis) during control conditions and after experimen

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Mallick, Subhashis. "Amplitude-variation-with-offset, elastic-impedence, and wave-equation synthetics — A modeling study." GEOPHYSICS 72, no. 1 (2007): C1—C7. http://dx.doi.org/10.1190/1.2387108.

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Amplitude-variation-with-offset (AVO) and elastic-impedance (EI) analysis use an approximate plane P-wave reflection coefficient as a function of angle of incidence. AVO and EI both can be used in a three-term or a two-term formulation. This study uses synthetic data to demonstrate that the P-wave primary reflections at large offsets can be contaminated by reflections from other wave modes that can affect the quality of three-term AVO or EI results. The coupling of P-waves and S-waves in seismic-wave propagation through finely layered media generates the interfering wave modes. A methodology s

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Yen, David H. Y. "Green's Function for the Damped Wave Equation on a Finite Interval Subject to Two Robin Boundary Conditions." Journal of Mechanics 19, no. 1 (2003): 257–62. http://dx.doi.org/10.1017/s1727719100004299.

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ABSTRACTThe Green's function for the damped wave equation on a finite interval subject to two Robin boundary conditions is studied. The problem for a semi-infinite interval with one Robin boundary is considered first by the Laplace transform method to establish the reflection principle at a Robin boundary. It is seen that the reflected wave generated by an exiting wave at a Robin boundary is a convolution involving the exiting wave and some kernel function. This generalizes the well known classical results for reflections at Dirichlet and Neumann boundaries. The reflection principle at a Robin

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Iverson, William P., Bill A. Fahmy, and Scott B. Smithson. "VpVs from mode‐converted P-SV reflections." GEOPHYSICS 54, no. 7 (1989): 843–52. http://dx.doi.org/10.1190/1.1442713.

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P-SV reflections are generated by a compressional‐wave source and result from P waves that are converted to shear (SV) waves upon reflection. Recording both the P and SV components yields compressional and shear data simultaneously. Verifying that the easily detected events really are P-SV reflections is accomplished by noting the good correlation of surface CDP data with vertical seismic profile (VSP) reflections. Stacking velocities from P-SV CDP gathers determine the [Formula: see text] product when source‐to‐receiver offset is less than the depth of the reflector but data from synthetic mo

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Qiu, Xinming, Chao Wang, Jun Lu, and Yun Wang. "Surface-Wave Extraction Based on Morphological Diversity of Seismic Events." Applied Sciences 9, no. 1 (2018): 17. http://dx.doi.org/10.3390/app9010017.

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It is essential to extract high-fidelity surface waves in surface-wave surveys. Because reflections usually interfere with surface waves on X components in multicomponent seismic exploration, it is difficult to extract dispersion curves of surface waves. To make matters worse, the frequencies and velocities of higher-mode surface waves are close to those of PS-waves. A method for surface-wave extraction is proposed based on the morphological differences between surface waves and reflections. Frequency-domain high-resolution linear Radon transform (LRT) and time-domain high-resolution hyperboli

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Wu, Yulang, and George A. McMechan. "True amplitude recovery in reverse time extrapolation of plane and spherical waves." GEOPHYSICS 83, no. 3 (2018): T103—T122. http://dx.doi.org/10.1190/geo2017-0425.1.

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A challenging outstanding problem in reverse time extrapolation is recovering accurate amplitudes at reflectors from the receiver wavefield. Various migrations have been developed to produce accurate image locations rather than correct amplitude information because of inadequate compensation of attenuation, dispersion, and transmission losses. We have evaluated the requirements, and determined the theoretical feasibility, of true amplitude recovery of 2D acoustic and elastic seismic data by using the analytic Zoeppritz equations for plane-wave reflection and transmission coefficients. Then, we

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Isaacson, Michael, Enda O'Sullivan, and John Baldwin. "Reflection effects on wave field within a harbour." Canadian Journal of Civil Engineering 20, no. 3 (1993): 386–97. http://dx.doi.org/10.1139/l93-054.

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The present paper outlines a numerical model for predicting the wave field in a harbour with partially reflecting boundaries, and describes laboratory tests undertaken to assess the model. The numerical model is based on linear diffraction theory and involves the application of a partial reflection boundary condition. By utilizing a wave doublet representation of the fluid boundaries instead of the usual wave source representation, the extension is made to general harbour configurations that include breakwaters. Numerical results are compared with known solutions for specific reference configu

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Wang, Zijian, Binkai Shi, and Chen Fang. "Characterisation of guided wave dispersion in isotropic tubes based on damping finite element boundaries." Insight - Non-Destructive Testing and Condition Monitoring 65, no. 1 (2023): 28–35. http://dx.doi.org/10.1784/insi.2023.65.1.28.

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Guided waves are suitable for non-destructive testing and structural health monitoring of tube-like structures. However, the dispersion phenomenon impedes the application of guided waves. Although the finite element (FE) method can simulate the guided wave propagation and help to study the dispersion phenomenon, boundary reflections can contaminate the wave field of interest and impede the FE simulation. In this paper, damping boundaries are developed as a set of FE frames with gradually increasing damping coefficients to alleviate boundary reflections. The wave signals simulated through the F

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Ursin, Bjørn, Martin Tygel, and Einar Iversen. "SS-traveltime parameters from PP and PS reflections." GEOPHYSICS 74, no. 4 (2009): R35—R47. http://dx.doi.org/10.1190/1.3147133.

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The SS-wave traveltimes can be derived from PP- and PS-wave data with the previously derived [Formula: see text] method. We have extended this method as follows. (1) The previous requirement that sources and receivers be located on a common acquisition surface is removed, which makes the method directly applicable to PS-waves recorded on the ocean bottom and PP-waves recorded at the ocean surface. (2) By using the concept and properties of surface-to-surface propagator matrices, the second-order traveltime derivatives of the SS-waves are obtained. In the same way as for the original [Formula:

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Tatavarti, V. S. N., David A. Huntley, and Anthony J. Bowen. "INCOMING AND OUTGOING WAVE INTERACTIONS ON BEACHES." Coastal Engineering Proceedings 1, no. 21 (1988): 9. http://dx.doi.org/10.9753/icce.v21.9.

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A technique to decompose colocated random field measurements of wave elevation and current velocity into incoming (shoreward propagating) and outgoing (seaward propagating) components is presented. This decomposition technique, which is less sensitive to noise, enables us to determine the frequency dependent reflection coefficients and also the relative phase between the incoming and outgoing waves. The method is applied to C2S2 and NSTS data sets, from beaches with wide ranging characteristics and wave regimes. The results demonstrate the selective nature of beach absorption/reflection charac

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Duchesne, Mathieu J., André J. M. Pugin, Gabriel Fabien-Ouellet, and Mathieu Sauvageau. "Detection of near-surface hydrocarbon seeps using P- and S-wave reflections." Interpretation 4, no. 3 (2016): SH21—SH37. http://dx.doi.org/10.1190/int-2015-0175.1.

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The combined use of P- and S-wave seismic reflection data is appealing for providing insights into active petroleum systems because P-waves are sensitive to fluids and S-waves are not. The method presented herein relies on the simultaneous acquisition of P- and S-wave data using a vibratory source operated in the inline horizontal mode. The combined analysis of P- and S-wave reflections is tested on two potential hydrocarbon seeps located in a prospective area of the St. Lawrence Lowlands in Eastern Canada. For both sites, P-wave data indicate local changes in the reflection amplitude and slow

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Assis, Carlos A. M., Sérgio A. M. Oliveira, Roseane M. Misságia, and Marco A. R. de Ceia. "Source wavelet and local wave propagation effects on the amplitude-variation-with-offset response of thin-layer models: A physical modeling study." GEOPHYSICS 82, no. 4 (2017): N27—N41. http://dx.doi.org/10.1190/geo2016-0262.1.

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In target layers with thicknesses below the vertical seismic resolution as thin layers, the tuning effect/interference between the wave propagation modes may increase the challenge of doing amplitude-variation-with-offset (AVO) analysis because it is difficult to recover the primary PP amplitudes embedded in the data by further seismic data processing. Thus, we have investigated the importance of the primary PP reflections, locally P-SV converted waves, and internal multiple reflections in the amplitude response of two thin-layer seismic physical models. One model consists of a thin water laye

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Nefedkina, T. V., P. A. Lykhin, and G. A. Dugarov. "DETERMINATION OF AZIMUTHAL ANISOTROPIC MEDIA ELASTIC PARAMETERS FROM MULTIWAVE AVOA DATA BY NONLINEAR OPTIMIZATION METHOD." Russian Journal of geophysical technologies, no. 2 (January 29, 2019): 14–26. http://dx.doi.org/10.18303/2619-1563-2018-2-2.

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In this paper, we investigate optimization algorithm of joint nonlinear AVOA inversion of PP+PS reflections in anisotropic media. Algorithm is based on the exact solution for PP and PS waves reflection coefficients in anisotropic HTI medium. The PP and PS wave’s reflections from the top of the anisotropic layer are examined. We use synthetic seismograms generated by ray method for the algorithm testing. We show that joint compressional and converted wave’s inversion allows increasing the robustness of the method and the accuracy of medium-parameter estimates. Coefficients of anisotropy are det

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Vasarmidis, Panagiotis, Vasiliki Stratigaki, Tomohiro Suzuki, Marcel Zijlema, and Peter Troch. "Internal Wave Generation in a Non-Hydrostatic Wave Model." Water 11, no. 5 (2019): 986. http://dx.doi.org/10.3390/w11050986.

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In this work, internal wave generation techniques are developed in an open source non-hydrostatic wave model (Simulating WAves till SHore, SWASH) for accurate generation of regular and irregular long-crested waves. Two different internal wave generation techniques are examined: a source term addition method where additional surface elevation is added to the calculated surface elevation in a specific location in the domain and a spatially distributed source function where a spatially distributed mass is added in the continuity equation. These internal wave generation techniques in combination w

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Monaldi, Lucas, Luis Gutiérrez Marcantoni, and Sergio Elaskar. "OpenFOAMTM Simulation of the Shock Wave Reflection in Unsteady Flow." Symmetry 14, no. 10 (2022): 2048. http://dx.doi.org/10.3390/sym14102048.

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This work studies the impact of a shock wave traveling with non-constant velocity over straight surfaces, generating an unsteady and complex reflection process. Two types of shock waves generated by sudden energy released are studied: cylindrical and spherical. Several numerical tests were developed considering different distances between the shock wave origin and the reflecting surface. The Kurganov, Noelle, and Petrova (KNP) scheme implemented in the rhoCentralFoam solver of the OpenFOAMTM software is used to reproduce the different shock wave reflections and their transitions. The numerical

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Liang, Chao, Ossian O’Reilly, Eric M. Dunham, and Dan Moos. "Hydraulic fracture diagnostics from Krauklis-wave resonance and tube-wave reflections." GEOPHYSICS 82, no. 3 (2017): D171—D186. http://dx.doi.org/10.1190/geo2016-0480.1.

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Fluid-filled fractures support guided waves known as Krauklis waves. The resonance of Krauklis waves within fractures occurs at specific frequencies; these frequencies, and the associated attenuation of the resonant modes, can be used to constrain the fracture geometry. We use numerical simulations of wave propagation along fluid-filled fractures to quantify fracture resonance. The simulations involve solution of an approximation to the compressible Navier-Stokes equation for the viscous fluid in the fracture coupled to the elastic-wave equation in the surrounding solid. Variable fracture aper

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Minato, Shohei, Takeshi Tsuji, Toshifumi Matsuoka, and Koichiro Obana. "Crosscorrelation of Earthquake Data Using Stationary Phase Evaluation: Insight into Reflection Structures of Oceanic Crust Surface in the Nankai Trough." International Journal of Geophysics 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/101545.

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Seismic interferometry (SI) has been recently employed to retrieve the reflection response from natural earthquakes. We perform experimental study to apply SI to Ocean Bottom Seismogram (OBS) records in the Nankai Trough, southwest Japan in order to reveal the relatively shallow geological boundaries including surface of oceanic crust. Although the local earthquakes with short raypath we use to retrieve reflection response are expected to contain the higher-frequency components to detect fine-scale structures by SI, they cannot be assumed as plane waves and are inhomogeneously distributed. Sin

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Igra, O., G. Hu, J. Falcovitz, and W. Heilig. "Blast Wave Reflection From Wedges." Journal of Fluids Engineering 125, no. 3 (2003): 510–19. http://dx.doi.org/10.1115/1.1567310.

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While a lot of attention was given to shock wave reflections from wedges during the past four decades, only little work was published regarding the similar case of blast wave reflection from wedges. In the present paper this subject is studied experimentally and theoretically/numerically. The obtained results show that the geometry of the reflected wave pattern is similar in the two cases when both incident waves have the same initial pressure jump across their fronts. However, different reflected pressure signatures (history) are observed in these two cases. The pressures obtained behind a re

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Holzschuh, Josef. "Low‐cost geophysical investigations of a paleochannel aquifer in the Eastern Goldfields, Western Australia." GEOPHYSICS 67, no. 3 (2002): 690–700. http://dx.doi.org/10.1190/1.1484512.

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Compressional (P) wave and shear (S) wave seismic reflection techniques were used to delineate the sand and gravel aquifer within a highly saline clay‐filled paleochannel in the Eastern Goldfields of Western Australia. The seismic refraction and gravity methods were also used to investigate the paleochannel. The unsaturated loose fine‐grained sand up to 10 m in depth at the surface is a major factor in degrading subsurface imaging. The seismic processing needed to be precise, with accurate static corrections and normal moveout corrections. Deconvolution enhanced the aquifer and other paleochan

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Thomas, Frédérique, Bruno Pannier, Nicolas Danchin, and Michel E. Safar. "Wave reflections in hypertension." Journal of Hypertension 37, no. 3 (2019): 555–62. http://dx.doi.org/10.1097/hjh.0000000000001928.

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Venugopal, Prem, and Luca Marinelli. "Localization of Arterial Bleeds Using Pulse Wave Reflections." Military Medicine 186, Supplement_1 (2021): 346–50. http://dx.doi.org/10.1093/milmed/usaa371.

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ABSTRACT Introduction Localization of internal arterial bleeds is necessary for treatment in the battlefield. In this article, we describe a novel approach that utilizes pulse wave reflections generated by a bleed to locate it. Materials and Methods To demonstrate our approach, velocity and diameter waveforms in the presence of bleeds were simulated using the 1D wave propagation equations in a straight-vessel model of the human thoracic aorta. The simulated waveforms were then decomposed into forward and backward components using wave intensity analysis. Reflections arising from the bleed were

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Karola, A., S. Tavakoli, T. Mikkola, J. Matusiak, and S. Hirdaris. "Absorption of wave reflections in way of an inlet boundary." IOP Conference Series: Materials Science and Engineering 1288, no. 1 (2023): 012013. http://dx.doi.org/10.1088/1757-899x/1288/1/012013.

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Abstract In recent years, Computational Fluid Dynamics (CFD) is increasingly becoming more attractive for the analysis of ship seakeeping. This is because of the increasing efficiency of computers and the accuracy of solvers (e.g. Reynold Navier Stokes Averaged – RANS) that may be more accurate in terms of idealizing nonlinear phenomena in comparison to potential flow methods. Notwithstanding this, RANS methods remain sensitive to accurate wave modelling across the fluid domain as well as the reflection of domain boundaries. This paper studies the effective absorption of the reflected waves fr

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Bourgault, Daniel, David C. Janes, and Peter S. Galbraith. "Observations of a Large-Amplitude Internal Wave Train and Its Reflection off a Steep Slope." Journal of Physical Oceanography 41, no. 3 (2011): 586–600. http://dx.doi.org/10.1175/2010jpo4464.1.

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Abstract Remote and in situ field observations documenting the reflection of a normally incident, short, and large-amplitude internal wave train off a steep slope are presented and interpreted with the help of the Dubreil–Jacotin–Long theory. Of the seven remotely observed waves that composed the incoming wave train, five were observed to reflect. It is estimated that the incoming wave train carried Ei = (24 ± 4) × 104 J m−1 to the boundary. The reflection coefficient, defined as the ratio of reflected to incoming wave train energies, is estimated to be R = 0.5 ± 0.2. This is about 0.4 lower t

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Qiang, Guo, Xiu Run Ge, and Ai Lan Che. "Formulas Deduction to Key Parameters of Multi-Reflection in GPR Survey." Advanced Materials Research 243-249 (May 2011): 1483–89. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.1483.

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The present paper is to analyses the key parameters of multi-reflection in GPR Survey. At first, it introduced the theory and methods for GPR result explanation. Then it proposed the necessity to work on multi-reflection analysis. For the complexity of multi-reflection, it emphatically worked on secondary reflection. According to the distinction of travel routes, the secondary reflection was divided into two cases. In the first case, the incident wave reflected twice at every interface and in the second case, the incident wave reflected for twice at every layer, meanwhile, the second reflected

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Wang, Yilin, Liangguo Dong, Chao Huang, Jianming Zhang, and Jianhua Wang. "Wave-equation reflection traveltime inversion constrained by selected reflection time windows." GEOPHYSICS 90, no. 3 (2025): U15—U30. https://doi.org/10.1190/geo2024-0082.1.

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Wave-equation reflection traveltime inversion is a powerful tool for reconstructing the low wavenumber components of the velocity model. One of the main challenges in reflection traveltime inversion is precisely estimating the reflection traveltime shifts between synthetic and observed data. Crosscorrelation is widely used for estimating reflection traveltime shifts. However, prestack seismic data usually contain multiple primary reflection events, and the reflection traveltime shifts are nonstationary. Because the global crosscorrelation result is generally dominated by strong reflections in

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Ting, Chih-Tai, Jaw-Wen Chen, Mau-Song Chang, and Frank Chi-Pong Yin. "Arterial Hemodynamics in Prehypertensives." International Journal of Hypertension 2019 (April 1, 2019): 1–9. http://dx.doi.org/10.1155/2019/3961723.

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Compared to age-matched normotensive adults, those with essential hypertension have been shown to have distinct arterial hemodynamic abnormalities consisting of increased peripheral resistance, pulse wave velocity, and wave reflection magnitude as well as decreased wave reflection time and aortic compliance. These abnormalities are further exacerbated by beta-adrenergic blockade. To see if there are similar hemodynamic abnormalities that antedate the onset of fixed hypertension, we compared age-matched normotensives with prehypertensives selected from patients undergoing diagnostic cardiac cat

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Lynn, Heloise B., Wallace E. Beckham, K. Michele Simon, C. Richard Bates, M. Layman, and Michael Jones. "P-wave and S-wave azimuthal anisotropy at a naturally fractured gas reservoir, Bluebell‐Altamont Field, Utah." GEOPHYSICS 64, no. 4 (1999): 1312–28. http://dx.doi.org/10.1190/1.1444636.

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Reflection P- and S-wave data were used in an investigation to determine the relative merits and strengths of these two data sets to characterize a naturally fractured gas reservoir in the Tertiary Upper Green River formation. The objective is to evaluate the viability of P-wave seismic to detect the presence of gas‐filled fractures, estimate fracture density and orientation, and compare the results with estimates obtained from the S-wave data. The P-wave response to vertical fractures must be evaluated at different source‐receiver azimuths (travelpaths) relative to fracture strike. Two perpen

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