Numerical simulation of an acoustic field generated by a phased arc array in a fluid-filled cased borehole

In this paper the characteristics of acoustic field for miniature cylindrical focused transducer with a hole was studied in order to instruct the optimization design of the transducer for both realizing visualization and improving the treatment effect. Then the acoustic field was simulated numerically with different parameters of hole. It is found that position of focus is almost unchanged but acoustic pressure amplitude declines. In addition the performance of transverse focusing for the focal plane and levels length of acoustic pressure are lowered. Moreover, if size of transducer and rigidity of material permit, the area and ratio of width to height for the hole should be reduced appropriately to improve the focusing properties. And it is deduced that area and ratio of width to height for the cylinder can be increased to achieve the same therapeutic effect with a fixed hole size.

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A semianalytical approach to calculate the reflected wave of an eccentric source in a borehole

Geophysics ◽

10.1190/geo2017-0660.1 ◽

2019 ◽

Vol 84 (1) ◽

pp. D1-D9

Author(s):

Feilong Xu ◽

Hengshan Hu

Keyword(s):

Acoustic Field ◽

Fourier Transforms ◽

Acoustic Source ◽

Reflection And Transmission ◽

Reflected Wave ◽

Reflection And Transmission Coefficient ◽

Simulation Error ◽

Pass Through ◽

Coefficient Method ◽

Cased Borehole

The acoustic field in a borehole is usually simulated under axisymmetric conditions. When the acoustic source deviates from the borehole axis, the field loses the axial symmetry property. We have developed a semianalytical approach to calculate the acoustic field excited by an eccentric source of limited size. The eccentric source is first decomposed into infinitely long multipole cylinder sources whose center axes pass through the eccentric point. Then, by applying the continuity of displacement and stress on the interfaces, we derive reflection coefficients by the generalized reflection and transmission coefficient method. Finally, the reflected wave is obtained after dual inverse Fourier transforms with respect to time and wavenumber. Numerical tests based on the reciprocity theorem are performed to validate this approach. The results indicate that the simulation error in every reciprocal model is negligible even if the eccentric distance of the acoustic source reaches two thirds of the radius of the borehole wall. We apply this semianalytical approach to simulate the reflected wave of an eccentric directional beam in a cased borehole.

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Direct Numerical Simulation of the acoustic field of a circular heated turbulent jet

Engineering Turbulence Modelling and Experiments 5 ◽

10.1016/b978-008044114-6/50068-5 ◽

2002 ◽

pp. 709-718

Author(s):

Bendiks Jan Boersma

Keyword(s):

Numerical Simulation ◽

Direct Numerical Simulation ◽

Acoustic Field ◽

Turbulent Jet

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Numerical Simulation of Airflow and Acoustic Field Around a Passenger Car Model Using Euler Approach and Hybrid Meshing

Recent Progress in Flow Control for Practical Flows ◽

10.1007/978-3-319-50568-8_16 ◽

2017 ◽

pp. 323-336

Author(s):

Oskar Szulc ◽

Piotr Doerffer

Keyword(s):

Numerical Simulation ◽

Acoustic Field ◽

Passenger Car ◽

Car Model ◽

Euler Approach

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THE FURTHER STUDY OF THE SPHEROIDAL BEAM EQUATION FOR FOCUSED FINITE-AMPLITUDE SOUND BEAMS

Journal of Computational Acoustics ◽

10.1142/s0218396x03001675 ◽

2003 ◽

Vol 11 (01) ◽

pp. 47-54 ◽

Cited By ~ 5

Author(s):

RONGMIN XIA ◽

WENDE SHOU ◽

GUOPING CHENG ◽

MEIDUN ZHANG

Keyword(s):

Numerical Simulation ◽

Parabolic Equation ◽

Acoustic Field ◽

High Frequency ◽

Finite Amplitude ◽

Beam Equation ◽

Circular Aperture ◽

Sound Beams

The spheroidal beam equation (SBE)1 is a parabolic equation, which fits for focused, high-frequency beams from a large circular aperture. Partition of the acoustic field is one of the very important aspects of the SBE. But the criterion of division has not been given. In this paper, the criterion and corresponding numerical simulation are introduced. At the same time, the comparison of the SBE solution with Lucas's parabolic equation is fulfilled.

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