Wave theory analysis for pulse propagated near sound channel axis in deep water

Optimization of Trimaran Design Configuration in Calm and Deep Water

Progress in Marine Science and Technology - HSMV 2020 ◽

10.3233/pmst200034 ◽

2020 ◽

Author(s):

Renato Skejic ◽

Sverre A. Alterskjær

Keyword(s):

Deep Water ◽

Optimization Procedure ◽

Wave Theory ◽

Point Of View ◽

Engineering Practice ◽

Total Resistance ◽

Operational Parameters ◽

Viscous Effects ◽

Greenhouse Gasses ◽

Hard Particles

The field of sea based modern shipping activities is constantly seeking for its improvements to achieve the economically justified operational patterns. In the same time, the sea transportation activities also need to satisfy currently imposed and, as well as, upcoming in the near future, safety and ecologically friendly footprint characteristics when it comes to the emission of greenhouse gasses and hard particles [1]. Fulfilment of the stated requirements consequently asks for the determination of certain vessels operational parameters such as the total resistance of a vessel which estimation is frequently carried out for predefined calm and deep-water environmental scenario. Current work is dealing with investigation of the total resistance parameter in calm and deep water for the preselected types of the trimaran ship hull configurations. The total resistance is estimated according to [2] recommended procedure through applicability of the robust and reliable method which is capable to address the problem of wave resistance prediction in calm and deep water. The method has origin in ordinary and modified Michell thin – ship wave theory by considering the viscous effects [3]. The differences between the utilized theories are discussed from the qualitative and quantitative point of view of the obtained results in comparison to the open source available theoretical experimental data and from the perspective of common engineering practice. Finally, based on the above description, the performed total resistance studies are used as a base for formulation of the optimization procedure which may be used in the trimaran vessel preliminary designs in the range of the forward speeds commonly expected during the normal operational life of the investigated trimaran vessel.

Download Full-text

The Sound Channel Axis in the Western Mediterranean

10.21236/ad0723865 ◽

1971 ◽

Author(s):

Eli J. Katz

Keyword(s):

Western Mediterranean ◽

Channel Axis ◽

Sound Channel

Download Full-text

Passive acoustic thermometry of the deep water sound channel using ambient noise

The Journal of the Acoustical Society of America ◽

10.1121/1.4830512 ◽

2013 ◽

Vol 134 (5) ◽

pp. 3983-3983

Author(s):

Katherine F. Woolfe ◽

Shane Lani ◽

Karim G. Sabra

Keyword(s):

Deep Water ◽

Ambient Noise ◽

Sound Channel ◽

Acoustic Thermometry ◽

Passive Acoustic

Download Full-text

THE CONVERTED HYDROACOUSTIC ARRAY "MG-10M" – A BASIC MODULE FOR A DEEP WATER ν-TELESCOPE

International Journal of Modern Physics A ◽

10.1142/s0217751x06033611 ◽

2006 ◽

Vol 21 (supp01) ◽

pp. 197-201

Author(s):

Y. KARLIK ◽

V. SVET

Keyword(s):

High Temperature ◽

Mediterranean Sea ◽

Deep Water ◽

Underwater Sound ◽

Good Tool ◽

Sound Channel ◽

Technical Parameters ◽

Basic Module ◽

Underwater Sound Channel ◽

The Mediterranean

The possibility of converted hydroacoustic arrays to create a module of deep water ν-Telescope is discussed. The array MC-10M is good tool to start the first real ocean experiments to investigate the problem of detecting neutrinos with energy 1018 eV. Technical parameters and systems which are necessary to create the module are presented. The Mediterranean Sea is an appropriate area for the first experiments due to existing of a deep underwater sound channel and stable high temperature. Some estimation of possible detecting volumes is presented. This project is continuation of works of authors in this direction, started in 1997.

Download Full-text

Nonlinear Dynamic Response of a Compliant Tower Under the Effect of Steady and Unsteady Sea States

Volume 3A: Structures, Safety and Reliability ◽

10.1115/omae2017-62449 ◽

2017 ◽

Cited By ~ 1

Author(s):

Konstantinos Chatziioannou ◽

Vanessa Katsardi ◽

Apostolos Koukouselis ◽

Euripidis Mistakidis

Keyword(s):

Structural Analysis ◽

Dynamic Response ◽

Deep Water ◽

Nonlinear Dynamic ◽

Wave Theory ◽

Random Wave ◽

Wave Loading ◽

Nonlinear Dynamic Response ◽

Steady Wave ◽

Compliant Tower

The purpose of this work is to highlight the importance of considering the actual nonlinear dynamic response for the analysis and design of fixed deep water platforms. The paper highlights the necessity of applying dynamic analysis through the comparison with the results obtained by the authors by applying static nonlinear analysis on the structure under examination. The example treated in the context of the present paper is a compliant tower, set-up in deep water. Nonlinearities are considered both for the calculation of the wave loadings and the structural analysis. The wave loading is based on linear random wave theory and comparisons are provided with the steady wave theories, Airy and Stokes 5th. The former solution is based on the most probable shape of a large linear wave on a given sea-state; the auto-correlation function of the underlying spectrum. On the other hand, in the field of structural analysis, two cases are considered for comparison, static analysis and time history dynamic analysis. For both types of analysis, two sub-cases are considered, a case in which geometric nonlinearity and nonlinearities related to the modelling of the soil are considered and a case in which the corresponding linear theories are employed (reference cases). The structural calculations were performed using the well-known structural analysis software SAP2000, which was enhanced by a special programming interface that was developed to calculate the wave loading and to directly apply the generated loads on the structural members. The results show that the consideration of the particle velocities associated with the linear random wave theory in the wave loading lead to significant differences with respect to the steady wave theories in terms of the displacements and stresses of the structure. Moreover, irrespectively of the adopted wave theory, the nonlinear analyses lead to significant discrepancies with respect to the linear ones. This is mainly associated with the nonlinear properties of the soil. Another source of discrepancies between the results of static and dynamic analyses stems from the change of the effective natural frequency of the structure when nonlinearities are considered.

Download Full-text

EFFECT OF HORIZONTAL INHOMOGENEITY OF THE OCEAN ON INTERFERENCE OF NEAR-AXIAL WAVES IN LONG-RANGE ACOUSTIC PROPAGATION

Journal of Computational Acoustics ◽

10.1142/s0218396x06003165 ◽

2006 ◽

Vol 14 (04) ◽

pp. 415-443 ◽

Cited By ~ 1

Author(s):

NATALIE S. GRIGORIEVA ◽

GREGORY M. FRIDMAN

Keyword(s):

Integral Representation ◽

Long Range ◽

Deterministic Model ◽

Sound Field ◽

Acoustic Propagation ◽

Time Of Arrival ◽

Channel Axis ◽

Sound Channel ◽

Narrow Strip ◽

Geometrical Acoustics

When the source and receiver are located close to the depth of the waveguide axis, there exist cusped caustics repeatedly along the axis. A description of the propagation of energy along the waveguide axis in terms of geometrical acoustics is not valid in neighborhoods of cusped caustics, because in these neighborhoods the waves associated with individual ray paths interfere with one another. Neighborhoods of interference grow with range, and at long distances they overlap. This results in the formation of a diffractive (as opposed to ray, i.e., geometrical acoustics) component of the field — the axial wave — that propagates along the sound-channel axis. In this paper, the integral representation of the axial wave obtained before for an arbitrary deep-water waveguide in a three-dimensional range-independent medium is generalized to a range-dependent ocean. The integral representation of the axial wave is derived with the use of solutions of the homogeneous Helmholtz equation concentrated near the sound-channel axis and which decrease exponentially outside a narrow strip containing the axis. The observed time-of-arrival patterns from a number of long-range ocean acoustic propagation experiments show early geometrical-like arrivals followed by a crescendo of energy that propagates along the sound-channel axis and is not resolved into individual arrivals. The practical application of the developed analytic expression for the sound field near the axis of an ocean type waveguide is the discrimination of noninterfering (resolved) and interfering (nonresolved) arrivals. In this paper, the axial wave is simulated for a deterministic model of a range-dependent medium, where the range-dependence results for such things as change in geographic location. The model is based on the information about sound-speed profiles as a function of range between the source and receiving array for the AET experiment. The sound source frequency is taken equal to 75Hz. The propagation range is 3250 km.

Download Full-text

Frustrated antiferromagnetic anisotropic Heisenberg model on two-dimensional systems: A linear spin-wave theory analysis

Physics Letters A ◽

10.1016/s0375-9601(97)00885-2 ◽

1998 ◽

Vol 238 (6) ◽

pp. 398-404 ◽

Cited By ~ 11

Author(s):

Abdelilah Benyoussef ◽

Abdelrhani Boubekri ◽

Hamid Ez-Zahraouy

Keyword(s):

Spin Wave ◽

Heisenberg Model ◽

Wave Theory ◽

Two Dimensional ◽

Theory Analysis ◽

Anisotropic Heisenberg Model ◽

Spin Wave Theory

Download Full-text

Integral properties of periodic gravity waves of finite amplitude

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1975.0018 ◽

1975 ◽

Vol 342 (1629) ◽

pp. 157-174 ◽

Cited By ~ 128

Keyword(s):

Solitary Wave ◽

Gravity Waves ◽

Deep Water ◽

Water Waves ◽

Wave Theory ◽

Finite Amplitude ◽

Cnoidal Wave ◽

The Mean ◽

Exact Relations ◽

Kinetic And Potential Energies

A number of exact relations are proved for periodic water waves of finite amplitude in water of uniform depth. Thus in deep water the mean fluxes of mass, momentum and energy are shown to be equal to 2T(4T—3F) and (3T—2V) crespectively, where T and V denote the kinetic and potential energies and c is the phase velocity. Some parametric properties of the solitary wave are here generalized, and some particularly simple relations are proved for variations of the Lagrangian The integral properties of the wave are related to the constants Q, R and S which occur in cnoidal wave theory. The speed, momentum and energy of deep-water waves are calculated numerically by a method employing a new expansion parameter. With the aid of Padé approximants, convergence is obtained for waves having amplitudes up to and including the highest. For the highest wave, the computed speed and amplitude are in agreement with independent calculations by Yamada and Schwartz. At the same time the computations suggest that the speed and energy, for waves of a given length, are greatest when the height is less than the maximum. In this respect the present results tend to confirm previous computations on solitary waves.

Download Full-text