Página 1 dos resultados de 153 itens digitais encontrados em 0.002 segundos

‣ Modeling arrival scattering due to surface roughness

Rodriguez, O. C.; Silva, A. J.; Gomes, J. P.; Jesus, S. M.
Fonte: European Conference on Underwater Acoustics Publicador: European Conference on Underwater Acoustics
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2010 Português
Relevância na Pesquisa
48.216816%
Signal scattering due to surface roughness constitutes one of the most important modeling problems in underwater acoustics when dealing with signal processing at large frequencies (i.e. above 1 kHz). Such modeling requires, in particular, realistic predictions of the ocean surface, which is usually perturbed by the propagation of swells and wind driven surface waves. Most of experimental studies had been dealing with short-range propagation, although it still remains unclear the separated impact of periodic vs. stochastic surface roughness on the arrival structure of received signals. The main purpose of the discussion presented in this paper is to clarify such issues through the calculation of impulse responses at high frequencies, at short and large ranges, using a ray tracing acustic propagation model. The results of the simulations are expected to improve strategies of signal processing when scattering affects the received signal.

‣ Combined adaptive time reversal and DFE technique for time-varying underwater communications

Vilaipornsawai, U.; Silva, A.; Jesus, S. M.
Fonte: European Conference on Underwater Acoustics Publicador: European Conference on Underwater Acoustics
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2010 Português
Relevância na Pesquisa
48.00321%
This work presents a combined geometry-adapted passive Time Reversal (pTR) and Decision Feedback Equalizer (DFE) technique for time-variant underwater communications. We consider sustainable high data rate communications between a moving source and/or a moving receiver array, i.e. there is the presence of geometry changes such as range and depth changes. Such geometry changes can be partially compensated by employing a proper frequency shift on the probe impulse response in the pTR processing. We then refer to the geometry-adapted pTR as Frequency Shift pTR (FSpTR). With dense and long receiver array, a pTR-based technique possesses pulse compression property and can eliminate Inter-Symbol Interference (ISI) problem in multipath static channels. However, with a practical-size array and time-varying channels, a residual ISI always exists. Hence, in this work, we apply an adaptive DFE to further mitigate the residual ISI from the FSpTR, and call the technique as FSpTR-DFE. Performance of the FSpTR-DFE is evaluated using both experimental and simulated data, where an information rate of 2000 bps and BPSK signaling are considered. The RADAR’07 experimental data and the simulated data of the south Elba site are considered. In both data sets...

‣ Linking acoustic communications and network performance: integration and experimentation of an underwater acoustic network

Caiti, N.; Grythe, Knut; Hovem, Jens M.; Jesus, S. M.; Lie, Arne; Munafò, Andrea; Reinen, Tor Arne; Silva, António J.; Zabel, Friedrich
Fonte: IEEE Xplore Publicador: IEEE Xplore
Tipo: Artigo de Revista Científica
Publicado em /10/2013 Português
Relevância na Pesquisa
48.399985%
Abstract—Underwater acoustic networks (UANs) are an emerging technology for a number of oceanic applications, ranging from oceanographic data collection to surveillance applications. However, their reliable usage in the field is still an open research problem, due to the challenges posed by the oceanic environment. The UAN project, a European-Union-funded initiative, moved along these lines, and it was one of the first cases of successful deployment of a mobile underwater sensor network integrated within a wide-area network, which included above water and underwater sensors. This contribution, together with a description of the underwater network, aims at evaluating the communication performance, and correlating the variation of the acoustic channel to the behavior of the entire network stack. Results are given based on the data collected during the UAN11 (May 2011, Trondheim Fjord area, Norway) sea trial. During the experimental activities, the network was in operation for five continuous days and was composed of up to four Fixed NOdes (FNOs), two autonomous underwater vehicles (AUVs), and one mobile node mounted on the supporting research vessel. Results from the experimentation at sea are reported in terms of channel impulse response (CIR) and signal-to-interference-plus-noise ratio (SINR) as measured by the acoustic modems during the sea tests. The performance of the upper network levels is measured in terms of round trip time (RTT) and probability of packet loss (PL). The analysis shows how the communication performance was dominated by variations in signal-to-noise ratio...

‣ Underwater acoustic communication using a time-reversal mirror approach

Silva, A.; Jesus, S. M.; Gomes, J.; Barroso, V.
Fonte: European Commission Publicador: European Commission
Tipo: Parte de Livro
Publicado em //2000 Português
Relevância na Pesquisa
48.444966%
This work presents a technique for reducing the intersymbol interference (ISI) in underwater coherent communications using time-reversal acoustics. The paper introduces a “virtual" time-reversal mirror (TRM) that is implemented electronically at the receiver array and simulates the kind of processing that would be done by an actual TRM during the reciprocal propagation stage. In both cases, a probe pulse sent by the transmitter/receiver located at the (physical or virtual) focal point and received at the array provides a template impulse response for undoing the effects of multipath by straightforward linear filtering. Very simple equalization algorithms may subsequently be used to decode the message. Channel variations between transmission of the probe and the actual message lead to mismatch that can impact the coherence of TRMs, and hence degrade the focusing power of the array. Computer simulations using a normal-mode propagation model in a reallistic shallow water scenario show that, even with high uncertainty in the transmitter and receiver relative positions, the virtual mirror can strongly reduce the effects of multipath. Although a multichannel equalizer attains a lower mean-square error, the "virtual" TRM can provide comparable results under low mismatch with much smaller complexity.

‣ The application of Tikhonov regularised inverse filtering to digital communication through multi-channel acoustic systems.

Dumuid, Pierre Marc
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012 Português
Relevância na Pesquisa
38.459504%
Communication between underwater vessels such as submarines is difficult to achieve over long distances using radio waves because of their high rate of absorption by water. Using underwater acoustic wave propagation for digital communication has the potential to overcome this limitation. In the last 30 years, there have been numerous papers published on the design of communication systems for shallow underwater acoustic environments. Shallow underwater acoustic environments have been described as extremely difficult media in which to achieve high data rates. The major performance limitations arise from losses due to geometrical spreading and absorption, ambient noise, Doppler spread and reverberation from surface and seafloor reflections (multi-path), with the latter being the primary limitation. The reverberation from multi-path in particular has been found to be very problematic when using the general communication systems that have been developed for radio wave communication systems. In the early 1990s, the principal means of combating multi-path in the shallow underwater environment was to use non-coherent modulation techniques. Coherent of obtaining a phase-lock and also that the environment was subject to fading. Designs have since been presented that addressed both of these problems by using a complex receiver design that involved a joint update of the phase-lock loop and the taps of the decision feedback filter (DFE). In recent years a technique known as time-reversal has been investigated for use in underwater acoustic communication systems. A major benefit of using the time-reversal filter in underwater acoustic communication systems is that it can provide a fast and simple method to provide a receiver design of low complexity. A technique that can be related to time-reversal and possibly used in underwater acoustics is Tikhonov regularised inverse filtering. The Tikhonov regularised inverse filter is a fast method of obtaining a stable inverse filter design by calculating the filter in the frequency domain using the fast Fourier transform...

‣ An analysis of the IIR an FIR Wiener filters with applications to underwater acoustics

Ruiz Fontes, Natanael
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Português
Relevância na Pesquisa
48.216816%
Approved for public release; Distribution is unlimited; A detailed analysis of the performance the Wiener optimal filter for estimating a signal in additive noise is carried out. A first order AR model is assumed for both the signal and noise. Both IIR and FIR forms of the filter are considered and expressions are derived for the processing gain, mean square error and signal distortion. These measures are plotted as a function of the model parameters. This analysis motivates a generalized form of the Wiener filter, which can improve the signal distortion. An analysis of this more general filter is then carried out. A practical noise removal algorithm based on short time filtering using the generalized filter is also described, and results of applying the algorithm to some typical underwater acoustic data are presented

‣ Horizontal steering control in docking the ARIES AUV; Horizontal steering control in docking the ARIES autonomous underwater vehicle

Tan, Wee Kiat
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xiv, 85 p. : ill.
Português
Relevância na Pesquisa
48.00321%
Approved for public release, distribution is unlimited; To keep the operational cost down and increase the mission time with minimum human intervention, autonomous recovery or docking operation of an Autonomous Underwater Vehicle (AUV) is required. Central to the successful autonomous docking process of the AUV is the capability of the AUV being able to track and steer itself accurately towards the dock which is constantly perturbed by wave motion effects. In addition, for accurate acoustic homing during the final stages of the docking, the AUV requires acoustic systems with high update rates. Equipped with acoustic modem, ARIES had experimentally been tested to have an update rate of only about 0.3 Hz. These delayed data can potentially cause a false commanded reference input to the tracking system in between the updates and cause ARIES to miss the moving cage's entrance. This thesis attempts to investigate the effectiveness on the use of cross track error and line of sight error sliding mode controller coupled with dynamic waypoints allocation in horizontal steering of ARIES in docking operations. In the absence of cage heading updates, a predictive method based on angular rate and direction of motion was used to estimate the dynamics of the moving cage. Further analysis was performed in order to understand the limitations of such an implementation.; Civilian...

‣ Performance evaluation of a prototype underwater short-range acoustic telemetry modem

Sommai, Pongsakorn.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xviii, 90 p. : ill. (some col.) ;
Português
Relevância na Pesquisa
58.74916%
Approved for public release; distribution is unlimited; This thesis documents the evaluation of the transmitter performance of a short-range underwater acoustic modem. This prototype modem was fabricated by contractor Teledyne Benthos, Inc. and is identified as Model ATM-90X. It was developed for use in the Seastar underwater Local Area Network (LAN). The ATM-90X modem is required to be capable of transferring large amounts of digital data at a range up to 500 m using the 33-55 kHz acoustic frequency band. The modem's transmitter performance was evaluated in term of its transmit frequency response, vertical beam pattern, and maximum source level. Underwater acoustic measurements were conducted in an anechoic water tank and the data were analyzed using signal processing techniques including Hilbert transforms, autocorrelation, and cross correlation. The transmission characteristics of the intended underwater acoustic communication channel were modeled to determine the required modem operating performance in the best and worst case situations. The measured performance characteristics were evaluated in the context of the communication link margin (i.e., the excess signal-to-noise ratio) associated with the modeled channels. The results show that (1) the modem transmit frequency response does not have acceptable flatness across the entire 33-55 kHz band; (2) the beam pattern in the vertical plane has a good hemisphere pattern; (3) estimated maximum source level is 175 dB re 1uPa-m at broadside of the modem. Based on the evaluated performance...

‣ The parametric propagation in underwater acoustics : experimental results

BOUTTARD, Etienne; LABAT, Valérie; BOU MATAR, Olivier; CHONAVEL, Thierry
Fonte: Société Française d'Acoustique Publicador: Société Française d'Acoustique
Português
Relevância na Pesquisa
48.444966%
In underwater acoustics, detection of buried objects in sediments (cables, mines, . . . ) is a complex problem. Indeed, in order to ensure sufficient penetration depth in marine sediments, low frequencies have to be used, implying a low resolution. A solution proposed to solve this problem is the parametric emission based on the nonlinear properties of seawater. This method can generate a low frequency wave from two directional high frequencies beams. The aim of this work is to present experimental results of a parametric propagation. Experiments have been carried out in a water tank in various configurations. These experimental measurements are then compared with simulation results obtained with a numerical model based on a fractional-step method presented at the Underwater Acoustic Measurements conference in 2011.

‣ Numerical modeling of underwater parametric propagation to detect buried objects

BOUTTARD, Etienne; LABAT, Valérie; BOU MATAR, Olivier
Fonte: Arts et Métiers ParisTech Publicador: Arts et Métiers ParisTech
Português
Relevância na Pesquisa
48.216816%
In underwater acoustics, detection of buried objects in sediments (cables, mines,…) is a complex problem. One reason is that acoustic attenuation in these sediments increases with frequency. To ensure sufficient penetration depth in marine sediments, low frequencies have to be used, implying a low resolution. A solution proposed to solve this problem is the parametric emission based on the nonlinear properties of the propagation medium. This method can generate a low frequency wave from two directional high frequencies beams. The parametric propagation is simulated in seawater and marine sediments. The model developed is based on the fractional-step numerical method introduced by Christopher and Parker [1]. In this method, the normal particle velocity is calculated plane by plane from the surface of the transducer to a specified distance. The effects of nonlinearity, attenuation and diffraction are calculated independently for each spatial step. Moreover, to reduce the number of spatial steps, a second order operator splitting scheme is used. The diffraction computation is based on a method of angular spectrum in the frequency domain where the field across a source plane is described by a spatial frequency distribution. To improve code stability...

‣ Sound propagation around underwater seamounts

Sikora, Joseph J., III
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 121 leaves
Português
Relevância na Pesquisa
48.143604%
This thesis develops and utilizes a method for analyzing data from the North Pacific Acoustic Laboratory's (NPAL) Basin Acoustic Seamount Scattering Experiment (BASSEX). BASSEX was designed to provide data to support the development of analytical techniques and methods which improve the understanding of sound propagation around underwater seamounts. The depth-dependent sound velocity profile of typical ocean waveguides force sound to travel in convergence zones about a minimum sound speed depth. This ducted nature of the ocean makes modeling the acoustic field around seamounts particularly challenging, compared to an isovelocity medium. The conical shape of seamounts also adds to the complexity of the scatter field. It is important to the U.S. Navy to understand how sound is diffracted around this type of topographic feature. Underwater seamounts can be used to conceal submarines by absorbing and scattering the sound they emit. BASSEX measurements have characterized the size and shape of the forward scatter field around the Kermit-Roosevelt Seamount in the Pacific Ocean. Kermit-Roosevelt is a large, conical seamount which shoals close to the minimum sound speed depth, making it ideal for study. Acoustic sources, including M-sequence and linear frequency-modulated sources...

‣ Model-based inverse problems in underwater acoustics

Jesus, S. M.
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Aula
Publicado em //2002 Português
Relevância na Pesquisa
48.216816%
Model-Based Processing (MBP) the problem the inversion methods real world examples conclusions; FCT

‣ Galerkin Methods for Parabolic and SCHR{\"O}DINGER Equations with Dynamical Boundary Conditions and Applications to Underwater Acoustics

Antonopoulou, D. C.; Dougalis, V. A.; Zouraris, G. E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/04/2009 Português
Relevância na Pesquisa
48.216816%
In this paper we consider Galerkin-finite element methods that approximate the solutions of initial-boundary-value problems in one space dimension for parabolic and Schr\"odinger evolution equations with dynamical boundary conditions. Error estimates of optimal rates of convergence in $L^2$ and $H^1$ are proved for the accociated semidiscrete and fully discrete Crank-Nicolson-Galerkin approximations. The problem involving the Schr\"odinger equation is motivated by considering the standard `parabolic' (paraxial) approximation to the Helmholtz equation, used in underwater acoustics to model long-range sound propagation in the sea, in the specific case of a domain with a rigid bottom of variable topography. This model is contrasted with alternative ones that avoid the dynamical bottom boundary condition and are shown to yield qualitatively better approximations. In the (real) parabolic case, numerical approximations are considered for dynamical boundary conditions of reactive and dissipative type.; Comment: 31 pages, 10 eps figures

‣ WWW Remote Control of the Underwater Acoustics Tank Laboratory of the Instituto de Acústica, CSIC, in Madrid

Ranz Guerra, Carlos; García, Mario
Fonte: Instituto de Pesquisas da Marinha Publicador: Instituto de Pesquisas da Marinha
Tipo: Comunicación de congreso Formato: 297027 bytes; application/pdf
Português
Relevância na Pesquisa
68.81876%
6 pages.-- PACS numbers: 43.58.-E, 43.30.-K.--Communication presented at the IV Encontro de Tecnología em Acústica Submarina (Rio de Janeiro, Brasil, 10-12 Nov. 1999).; The Underwater Acoustics Tank Laboratory at the Instituto de Acústica, CSIC, has been recently reshaped. The new tank framework introduces the installation of two bridges with an automatic control on the three coordinates and the angle (Ranz & Cobo, 1998). In the last months the hardware and software necessary for sequencing the signal acquisition with the bridges motion has been incorporated. While being always necessary one operator, at the laboratory, to survey the tank activities, the actual structure allows to carry the full control of the tank motion as well as the signal acquisition out by any person, at any place, through the usual www network support. This paper describes the actual installation and the facilities involved.; The authors are willing to acknowledge the help given by the PN CYTMAR and to the CSIC for their financial support to enlarge the capabilities of the Hydroacoustic Tank of the Instituto de Acústica.; Peer reviewed

‣ The influence of ocean waves in shallow water problems

Kormann, Jean; Ranz Guerra, Carlos; Fernández, Alejandro
Fonte: Scientific Society for Optics, Acoustics, Motion Picture and Theater Technology (Hungary) Publicador: Scientific Society for Optics, Acoustics, Motion Picture and Theater Technology (Hungary)
Tipo: Comunicación de congreso Formato: 390593 bytes; application/pdf
Português
Relevância na Pesquisa
48.012656%
5 pages.-- Communication presented at ForumAcusticum 2005 Budapest: "Acoustics: Science and Technology for Knowledge Based Society and Healthy Environment" (Aug 29-Sep 2, 2005).; In this paper we present the influence of ocean waves in shallow water scenarios which have geometric dimensions of about several times the acoustic wavelength. Typically, this concerns coastal zones. It is well known that ocean waves are a source of scattering, have dispersive behaviour, and that at low frequencies are a source of noise. We will base our work on measurements realized in shallow water conditions, an attempt to model ocean waves and include them in existing codes of acoustic propagation using finite difference schemes. Additionally, we will compare the differences between measurements and prediction models and try to discuss the reliability of the models for the Shallow water case.; Peer reviewed

‣ Underwater acoustic tank evaluation of acoustic properties of samples using spectrally dense signals

Ranz Guerra, Carlos; Cobo, Pedro
Fonte: Deutsche Gesellschaft für Akustik Publicador: Deutsche Gesellschaft für Akustik
Tipo: Comunicación de congreso Formato: 745842 bytes; application/pdf
Português
Relevância na Pesquisa
38.676362%
4 pp.-- Comunicación presentada en: Joint Meeting "Berlin 99": 137th regular meeting of the Acoustical Society of America ; 2nd convention of the EAA: Forum Acusticum - integrating the 25th German Acoustics DAGA Conference. Berlin, March 14-19, 1999.; This paper deals with exploring the availability and reliability of subtraction techniques, based on spectrally dense signals such as Maximun Length Sequences, in evaluating the echo reduction losses of samples of interest underwater acoustics. These techniques, first employed in air acoustics, were adapted to the underwater environment. Experimental results show how a measurement can be accomplished and the limitations produced by the actual available combination of soft, hardware and tank and sample dimensions.; The authors wish to acknowledge the help given by the CICYT, Project AMB97-1175-CO301, for having the opportunity to use the software, hardware and related facilities in carrying out the work described by this paper.; Peer reviewed

‣ Control remoto del tanque de experimentación hidroacústica del Instituto de Acústica del CSIC

Ranz Guerra, Carlos; García, Mario
Fonte: Sociedad Española de Acústica Publicador: Sociedad Española de Acústica
Tipo: Comunicación de congreso Formato: 340405 bytes; application/pdf
Português
Relevância na Pesquisa
48.448213%
8 pp.-- PACS nrs.: 43.58.-E, 43.30.-K.-- Comunicación presentada en los siguientes congresos: XXX Jornadas Nacionales de Acústica – TecniAcústica 1999. Encuentro Ibérico de Acústica (Ávila, 20-22 Octubre 1999).; Publicado en número especial de la Revista de Acústica: Vol 30(1999).; [EN] The Underwater Acoustics Tank Laboratory at the Instituto de Acústica, CSIC, has been recently reshaped. The new tank framework introduces the installation of two bridges with an automatic control on the three coordinates and the angle (Ranz & Cobo, 1998). In the last months the hardware and software necessary for sequencing the signal acquisition with the bridges motion has been incorporated. While being always necessary one operator, at the laboratory, to survey the tank activities, the actual structure allows to carry the full control of the tank motion as well as the signal acquisition out by any person, at any place, through the usual www network support. This paper describes the actual installation and the facilities involved.; [ES] El Tanque de Experimentación en Acústica Subacuática instalado en el Instituto de Acústica, CSIC, ha sido renovado recientemente. La renovación a la que hacemos referencia ha consistido en sustituir el viejo puente soporte del emisor...

‣ La acústica submarina y su desarrollo desde la creación del Instituto de Acústica

Ranz Guerra, Carlos; Cobo, Pedro; Carbó, Rafael; Santiago Páez, José Salvador; Soler, A. M.; Briones, J. M.; Jimeno, I.; Muñoz, N.; Camarasa, M.; Recuero López, Manuel
Fonte: Sociedad Española de Acústica Publicador: Sociedad Española de Acústica
Tipo: Artículo Formato: 272098 bytes; application/pdf
Português
Relevância na Pesquisa
49.05427%
PACS: 43.30.Xm; 43.30.Yj; 43.30.Vh; 43.30.Nb; 43.30.Ma.-- Publicado en el Vol. XXXI, núm. 3-4, tercer y cuarto trimestre 2000 de la Revista de Acústica: Número especial dedicado al XXV Aniversario del Instituto de Acústica del C.S.I.C.; [ES] La Acústica Submarina fue una de las líneas de la Acústica que se desarrollan en el Instituto desde los primeros tiempos. Este trabajo describe como se inició, cómo se desarrolló y el estado actual de este campo.; [EN] Underwater Acoustics was one line of Acoustics first developped at the Instituto de Acústica. This paper presents a description of the activities in the underwater field, done since 1969, when the Underwater Tank was installed, up to the present times.; Peer reviewed

‣ Underwater noise impact of offshore wind farms during construction and operation phases

Cobo, Pedro; Kormann, Jean; Ranz Guerra, Carlos
Fonte: International Institute of Acoustics and Vibration Publicador: International Institute of Acoustics and Vibration
Tipo: Comunicación de congreso Formato: 577635 bytes; application/pdf
Português
Relevância na Pesquisa
48.143604%
Communication presented at the 14th International Congress on Sound Vibration, Cairns, Australia, 9-12 July 2007.; The two potentially noisier phases of an offshore wind farm are construction and operation. During the construction phase, high noise levels are radiated to the environment, both in air and water, due to engineering works such as pile driving. In the operation phase, the acoustic power radiated by each wind turbine is much lesser, but their usual life-span is 20-25 years. The aim of this paper is to describe a normal mode propagation model designed to predict the underwater noise impact afforded for an offshore wind farm in both phases. The model needs as inputs the acoustic data of the underwater sources (power level and spectrum), the oceanographic data of the medium (sound velocity and density in water and sediments, wind speed, depth, acoustic spreading law in the area) and the coordinates of the wind turbines. As a result, the model provides both the 2D overall noise map around the farm or the overall noise level along a line, as compared to the background noise.; This research has been supported by the CSIC, through Project PIF 200530F0081.; Peer reviewed

‣ Implementation of a computational model for random directional seas and underwater acoustics

Bayindir, Cihan
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
58.444966%
Kirby, James T.; Acoustic wave propagation in the ocean is an old and interesting problem. In the literature the problem of interaction of acoustic waves with the ocean surface has drawn the attention of many researchers. This interaction problem is a very complicated problem due to many physical processes involved. Some of the important factors on the ocean surface which affects underwater communications are presence of waves, turbulence generated by wind input, wave breaking, white capping, bubbles and density, salinity and temperature effects. In this thesis, the effect of linear and nonlinear surface gravity waves on high frequency acoustic propagation is discussed. Realistic models of linear and nonlinear surface gravity waves, which solve the exact governing equations, are created, and these models are coupled with an acoustic Gaussian beam tracing program called Bellhop. Since Bellhop is not capable of accounting for out of plane scattering of acoustic rays, coupling is done only for two spatial dimensions, one horizontal and one vertical. The wave model provides velocity components in the normal direction to the surface. These velocity components are used in the Doppler frequency shift calculations of acoustic rays generated by Bellhop. Data from an acoustic experiment are taken as experimental results and coupled wave-acoustic model has been run with the same conditions and same geometric layout of experiments. Comparisons between experimental results and coupled wave-acoustic model results are presented and the limits of model validity are discussed.; University of Delaware...