Nonlinear Acoustic Propagation Applied to Brassiness Studies, a New Simulation Tool in the Time Domain

2017 ◽  
Vol 103 (1) ◽  
pp. 67-79 ◽  
Author(s):  
S. Maugeais ◽  
J. Gilbert
Keyword(s):  
Time Domain ◽  
Acoustic Propagation ◽  
Simulation Tool ◽  
Nonlinear Acoustic ◽  
The Time Domain

A Moving Zonal Method in the Time-Domain Simulation for Acoustic Propagation

2010 ◽  
Author(s):  
Z. Charlie Zheng ◽  
Guoyi Ke
Keyword(s):  
Long Range ◽  
Time Domain ◽  
Region Of Interest ◽  
Acoustic Propagation ◽  
Coordinate Frame ◽  
Computational Domain ◽  
Perfectly Matched Layers ◽  
Zonal Method ◽  
Moving Domain ◽  
The Time Domain

Conventional time-domain schemes have limited capability in modeling long-range acoustic propagation because of the vast computer resources needed to cover the entire region of interest with a computational domain. Many of the long-range acoustic propagation problems need to consider propagation distances of hundreds or thousands of meters. It is thus very difficult to maintain adequate grid resolution for such a large computational domain, even with the state-of-the-art capacity in computer memory and computing speed. In order to overcome this barrier, a moving zonal-domain approach is developed. This concept uses a moving computational domain that follows an acoustic wave. The size and interval of motion of the domain are problem dependent. In this paper, an Euler-type moving domain in a stationary coordinate frame is first tested. Size effects and boundary conditions for the moving domain are considered. The results are compared and verified with both analytical solutions and results from the non-zonal domain. Issues of using the moving zonal-domain with perfectly-matched layers for the free-space boundary are also discussed.

Numerical Simulation of Ship Motion in Offshore and Harbour Areas

2008 ◽  
Author(s):  
Erik Damgaard Christensen ◽  
Bjarne Jensen ◽  
Simon Brandi Mortensen ◽  
Hans Fabricius Hansen ◽  
Jens Kirkegaard
Keyword(s):  
Time Domain ◽  
Open Water ◽  
The Body ◽  
Hydrodynamic Characteristics ◽  
Simulation Tool ◽  
Response Functions ◽  
Wave Forcing ◽  
Mooring Forces ◽  
The Time Domain ◽  
Equations Of Motions

A method for simulating the motions and mooring forces of a moored ship subject to wave forcing has been further developed and validated for both the open water case and inside harbour areas. The method was originally developed and reported in Bingham (2000). The simulation tool is named WAMSIM and it solves the equations of motions in the time domain. The package applies the WAMIT® model to provide the frequency domain hydrodynamic characteristics (the frequency response functions or FRFs) of the body. Examples from both open waters and enclosed waters in harbours are presented.

THREE TIME-DOMAIN COMPUTATIONAL MODELS FOR QUASI-STANDING NONLINEAR ACOUSTIC WAVES, INCLUDING HEAT PRODUCTION

2006 ◽  
Vol 14 (02) ◽  
pp. 143-156 ◽  
Author(s):  
CHRISTIAN VANHILLE ◽  
CLEOFÉ CAMPOS-POZUELO
Keyword(s):  
Time Domain ◽  
Acoustic Waves ◽  
Computational Models ◽  
High Amplitude ◽  
Ultrasonic Waves ◽  
Physical Models ◽  
Industrial Processing ◽  
Strongly Nonlinear ◽  
Nonlinear Acoustic ◽  
The Time Domain

Applications of high-amplitude acoustic or ultrasonic waves in industrial processing require a good knowledge of the nonlinear pressure field, as well as the heat produced by the wave. In this article a new time-domain algorithm solving a second-order nonlinear wave equation written in Lagrangian coordinates and valid for any fluid is presented. The new model is compared with two others which were previously developed, corresponding to the two other possible physical approaches. This paper discusses the limits of application of every approach and the suitability of every one to model nonlinear acoustic waves in resonators. Conclusions about the applicability of the physical models are given. The time-domain character of the models allows the development of a new algorithm to calculate the temperature evolution inside a resonator due to acoustic losses. This algorithm is presented here and applied to strongly nonlinear waves for which the nonlinear attenuation is dominant. Several kinds of time functions for excitation can be considered in the models. The strongly nonlinear resonator response to a short pulsed signal is analyzed to show the efficiency of the time-domain numerical model.

Development of a Multi-Body Vessel Dynamics Simulation Tool

2009 ◽  
Author(s):  
Xiaochuan Yu ◽  
Chandan Lakhotia ◽  
Jeffrey M. Falzarano
Keyword(s):  
Time Domain ◽  
Wave Force ◽  
Dynamics Simulation ◽  
Simulation Tool ◽  
Sea State ◽  
Body Dynamics ◽  
Constant Coefficients ◽  
The Time Domain ◽  
Multi Body ◽  
The Given

Multi-body dynamics is important in many fields of engineering. For the at-sea transfer of cargo between ships multi-body dynamics is particularly important. There are several methods of transferring solid cargo between vessels and these include by crane or by ramp. Each method is extremely sensitive to the relative motions between the various vessels. An accurate modeling of the vessels’ motions is critical in determining limiting sea state conditions and in suggesting how to improve the given system. There are various levels of approximation which are commonly employed to model vessel hydrodynamics and we hope to eventually determine what level of approximation is appropriate for a given situation. In this paper, we will compare the effects of considering as well as ignoring the multi-body hydrodynamic interactions using a constant coefficients approximation to the time domain radiated wave force.

scholarly journals Staggered-grid finite-difference acoustic modeling with the Time-Domain Atmospheric Acoustic Propagation Suite (TDAAPS).

2005 ◽  
Author(s):  
David Franklin Aldridge ◽  
Sandra L. Collier ◽  
David H. Marlin ◽  
Vladimir E. Ostashev ◽  
Neill Phillip Symons ◽  
...  
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Acoustic Propagation ◽  
Acoustic Modeling ◽  
Staggered Grid ◽  
The Time Domain

Apodisation in the time domain

1992 ◽  
Vol 2 (4) ◽  
pp. 615-620
Author(s):  
G. W. Series
Keyword(s):  
Time Domain ◽  
The Time Domain
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