Dynamic time reversal of randomly backscattered acoustic waves

1999 ◽  
Vol 47 (2) ◽  
pp. 175-181 ◽  
Author(s):  
A Tourin ◽  
A Derode ◽  
M Fink
1999 ◽  
Vol 105 (2) ◽  
pp. 956-956
Author(s):  
Arnaud Tourin ◽  
Arnaud Derode ◽  
Mathias Fink

APL Photonics ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 030806 ◽  
Author(s):  
R. Konoike ◽  
T. Asano ◽  
S. Noda

2006 ◽  
Author(s):  
Emmanuel Bossy ◽  
Gabriel Montaldo ◽  
Michael Tanter ◽  
Benoit Forget ◽  
François Ramaz ◽  
...  

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1419 ◽  
Author(s):  
Hamidreza Karami ◽  
Mohammad Azadifar ◽  
Amirhossein Mostajabi ◽  
Marcos Rubinstein ◽  
Hossein Karami ◽  
...  

In this work, we present a novel technique to locate partial discharge (PD) sources based on the concept of time reversal. The localization of the PD sources is of interest for numerous applications, including the monitoring of power transformers, Gas Insulated Substations, electric motors, super capacitors, or any other device or system that can suffer from PDs. To the best of the authors’ knowledge, this is the first time that the concept of time reversal is applied to localize PD sources. Partial discharges emit both electromagnetic and acoustic waves. The proposed method can be used to localize PD sources using either electromagnetic or acoustic waves. As a proof of concept, we present only the results for the electromagnetic case. The proposed method consists of three general steps: (1) recording of the waves from the PD source(s) via proper sensor(s), (2) the time-reversal and back-propagation of the recorded signal(s) into the medium using numerical simulations, and (3) the localization of focal spots. We demonstrate that, unlike the conventional techniques based on the time difference of arrival, the proposed time reversal method can accurately localize PD sources using only one sensor. As a result, the proposed method is much more cost effective compared to existing techniques. The performance of the proposed method is tested considering practical scenarios in which none of the former developed methods can provide reasonable results. Moreover, the proposed method has the unique advantage of being able to locate multiple simultaneous PD sources and doing so with a single sensor. The efficiency of the method against the variation in the polarization of the PDs, their length, and against environmental noise is also investigated. Finally, the validity of the proposed procedure is tested against experimental observations.


2013 ◽  
Author(s):  
Yegor Sinelnikov ◽  
Alexander Sutin ◽  
Sergey Tsyuryupa ◽  
Armen Sarvazyan

2001 ◽  
Vol 09 (03) ◽  
pp. 993-1003 ◽  
Author(s):  
ARNAUD DERODE ◽  
MICKAËL TANTER ◽  
ARNAUD TOURIN ◽  
LAURENT SANDRIN ◽  
MATHIAS FINK

In classical mechanics, a time-reversal experiment with a large number of particles is impossible. Because of the high sensitivity to initial conditions, one would need to resolve the positions and velocities of each particle with infinite accuracy. Thus, it would require an infinite amount of information, which is of course out of reach. In wave physics however, the amount of information required to describe a wave field is limited and depends on the shortest wavelength of the field. Thus we can propose an acoustic equivalent of the experiment we mentioned above. We start with a coherent transient pulse, let it propagate through a disordered highly scattering medium, then record the scattered field and time-reverse it: surprisingly, it travels back to its initial source, which is not predictable by usual theories for random media. Indeed, to study waves propagation in disordered media theoreticians, who find it difficult to deal with one realization of disorder, use concepts defined as an average over the realizations, which naturally leads to the diffusion approximation. But the corresponding equation is not time-reversal invariant and thus fails in describing our experiment. Then, to understand our experimental results and try to predict new ones, we have developed a finite elements simulation based on the real microscopic time-invariant equation of propagation. The experimental and numerical results are found to be in very good agreement.


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