Near field acoustic source identification based on numerical models and operational pressure data

1998 ◽  
Vol 103 (5) ◽  
pp. 2815-2815
Author(s):  
Paul Sas ◽  
Peter Mas
Keyword(s):  
Source Identification ◽  
Numerical Models ◽  
Near Field ◽  
Pressure Data ◽  
Acoustic Source

Near-field tsunami forecasting from cabled ocean bottom pressure data

2009 ◽  
Vol 114 (B6) ◽  
Author(s):  
Hiroaki Tsushima ◽  
Ryota Hino ◽  
Hiromi Fujimoto ◽  
Yuichiro Tanioka ◽  
Fumihiko Imamura
Keyword(s):  
Near Field ◽  
Ocean Bottom ◽  
Bottom Pressure ◽  
Pressure Data ◽  
Ocean Bottom Pressure ◽  
Tsunami Forecasting

A Two-Region Model for Gradient Modification of Salt-Gradient Solar Ponds by Radial Injection

1996 ◽  
Vol 118 (1) ◽  
pp. 37-44 ◽  
Author(s):  
G. A. Eghneim ◽  
S. J. Kleis
Keyword(s):  
Turbulence Model ◽  
Field Model ◽  
Numerical Study ◽  
Numerical Models ◽  
Domain Boundary ◽  
Near Field ◽  
Solar Ponds ◽  
Numerical Predictions ◽  
Region Model ◽  
Salt Gradient

A combined experimental and numerical study was conducted to support the development of a new gradient maintenance technique for salt-gradient solar ponds. Two numerical models were developed and verified by laboratory experiments. The first is an axisymmetric (near-field) model which determines mixing and entrainment in the near-field of the injecting diffuser by solving the conservation equations of mass, momentum, energy, and salt. The model assumes variable properties and uses a simple turbulence model based on the mixing length hypothesis to account for the turbulence effects. A series of experimental measurements were conducted in the laboratory for the initial adjustment of the turbulence model and verification of the code. The second model is a one-dimensional far-field model which determines the change of the salt distribution in the pond gradient zone as a result of injection by coupling the near-field injection conditions to the pond geometry. This is implemented by distributing the volume fluxes obtained at the domain boundary of the near-field model, to the gradient layers of the same densities. The numerical predictions obtained by the two-region model was found to be in reasonable agreement with the experimental data.

scholarly journals Acoustic source imaging using numerical models

1988 ◽  
Vol 84 (S1) ◽  
pp. S171-S171
Author(s):  
Robert J. Bernhard ◽  
B. K. Gardner
Keyword(s):  
Numerical Models ◽  
Acoustic Source ◽  
Source Imaging

scholarly journals HARBOUR DESIGN INCLUDING SEDIMENTOLOGICAL PROBLEMS USING MAINLY NUMERICAL TECHNICS

1980 ◽  
Vol 1 (17) ◽  
pp. 132 ◽  
Author(s):  
B. Latteux
Keyword(s):  
Continuity Equation ◽  
Numerical Study ◽  
Numerical Models ◽  
Near Field ◽  
Step Method ◽  
Access Channel ◽  
Load Transport ◽  
Erosion Area ◽  
Bed Load Transport ◽  
Water Height

For most of the needed studies for the design of Calais harbour enlargement works, the "Laooratoire National d'Hydraulique" chose to use numerical models. This approach includes the determination of currents around and insiae the new outer-haroour, just as the evaluation of the project sedimentologic impact and of the long-term evolution of a bank nameo "le Riaen de ia Rade", edging the access channel. Current studies were performed using four nested bidimensionnal computer models fitted on field data and supplying in eac;i point the depth-averaged velocity and the total water height. These four models are based on an implicite finite difference fractionnal step method. Besides for the very near field model the method is especially elaborated to enable' the detailed reproduction of eddies and flow separations. The sedimentological numerical study is based upon current models results : the bed-load transport is computed from the depth-averaged velocity and the water height previously determined using an empirical formula, and tne continuity equation applied to this loaa transport gives then the bed evolution. As soon as the depth variation is significant enough to react on the flow pattern, current fielos are readjusted oy a simple metnod based on flow continuity equation. This numerical model, applied to the near fielo, has given an evaluation of the sedimentological impact of the haroour enlargement project : - strong erosion in front of the new harbour due to current strengthening ; - accretion on each side of this erosion area, especially in the channel ; - bar formation at the harbour entrance.

scholarly journals Enhancement of two-dimensional acoustic source identification with Fourier-based deconvolution beamforming

2016 ◽  
Vol 18 (5) ◽  
pp. 3337-3361 ◽  
Author(s):  
Zhigang Chu ◽  
Yang Yang ◽  
Linbang Shen ◽  
Guoli Ping
Keyword(s):  
Source Identification ◽  
Two Dimensional ◽  
Acoustic Source

Acoustic Double Holography Method and its Application to Engine Noise Research

1997 ◽  
Author(s):  
Milsuo Nakano ◽  
Masao Nagamatsu ◽  
Kohei Suzuki ◽  
Takuya Yoshimura
Keyword(s):  
Noise Source ◽  
Near Field ◽  
Wave Length ◽  
Pressure Data ◽  
Acoustic Holography ◽  
Engine Noise ◽  
Simplified Approach ◽  
Noise Shielding ◽  
Full Load Operation ◽  
Control Work

Abstract The acoustic holography (AH) method with single measuring plane has been well known as the conventional method and can be implemented by far field measurement with simple instruments. However, the noise source resolution of the AH is not sufficient. In order to improve the resolution in the noise source identification, several kinds of the acoustic holography methods have been so far proposed. For example, the near field acoustic holography (NAH) can provide high and accurate resolution of the holography by the nearfield measurement. However, the nearfield measurement within one wave length is sometimes impossible in the actual circumstances. The Acoustic Double Holography (A D H) proposed in this paper is a simplified approach with higher resolution of the noise source locations than that of the conventional AH methods. The ADH method basically uses dual measuring planes and does not require nearfield measurement. The sound pressure data detected on the rear plane are transformed into the virtual pressure data on the front plane taking into account of the distance between the plane and the object. Comparing the virtual pressure data with the actual data measured on the front plane, resolution on holography can be improved significantly. Computer simulation and an experiment with two loud speakers were executed in order to confirm the fundamental feature of the proposed method. Several advantages on the method with respect to resolution over the conventional AH method were discussed. Furthermore, the ADH measurement was carried out on running engine under the full load operation. Through these results, the highly noise radiating areas on the engine surface were detected and reduced with noise shielding material. The overall engine noise level was reduced by 1.5dBA as the first stage in this noise control work.

Sensor Planning for Model-Based Acoustic Source Identification

2020 ◽  
Author(s):  
Luke Calkins ◽  
Reza Khodayi-mehr ◽  
Wilkins Aquino ◽  
Michael M. Zavlanos
Keyword(s):  
Source Identification ◽  
Acoustic Source ◽  
Sensor Planning ◽  
Model Based
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