Retrofocusing of Acoustic Wave Fields by Iterated Time Reversal
(2003) In Technical Report LUTEDX/(TEAT-7115)/1-36/(2003) TEAT-7115.- Abstract
- In the present paper an iterative time-reversal algorithm, that retrofocuses an
acoustic wave ﬁeld to its controllable part is established. For a ﬁxed temporal
support, i.e., transducer excitation time, the algorithm generates an optimal
retrofocusing in the least-squares sense. Thus the iterative time-reversal algorithm
reduces the temporal support of the excitation from the requirement of
negligible remaining energy to the requirement of controllability. The timereversal
retrofocusing is analyzed from a boundary control perspective where
time reversal is used to steer the acoustic wave ﬁeld towards a desired state.
The wave ﬁeld is controlled by transducers located... (More) - In the present paper an iterative time-reversal algorithm, that retrofocuses an
acoustic wave ﬁeld to its controllable part is established. For a ﬁxed temporal
support, i.e., transducer excitation time, the algorithm generates an optimal
retrofocusing in the least-squares sense. Thus the iterative time-reversal algorithm
reduces the temporal support of the excitation from the requirement of
negligible remaining energy to the requirement of controllability. The timereversal
retrofocusing is analyzed from a boundary control perspective where
time reversal is used to steer the acoustic wave ﬁeld towards a desired state.
The wave ﬁeld is controlled by transducers located at subsets of the boundary,
i.e., the controllable part of the boundary.
The time-reversal cavity and time-reversal mirror cases are analyzed. In the
cavity case, the transducers generate a locally plane wave in the fundamental
mode through a set of ducts. Numerical examples are given to illustrate the
convergence of the iterative time-reversal algorithm. In the mirror case, a
homogeneous half space is considered. For this case the analytic expression
for the retrofocused wave ﬁeld is given for ﬁnite temporal support. It is shown
that the mirror case does not have the same degree of steering as the cavity
case. It is also shown that the pressure can be perfectly retrofocused for
inﬁnite temporal support. Two examples are given that indicate that the
inﬂuence of the evanescent part of the wave ﬁeld is small. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/530517
- author
- Jonsson, B Lars G; Gustafsson, Mats ^{LU} ; Weston, Vaughan H. and de Hoop, Maarten V.
- organization
- publishing date
- 2003
- type
- Book/Report
- publication status
- published
- subject
- in
- Technical Report LUTEDX/(TEAT-7115)/1-36/(2003)
- volume
- TEAT-7115
- pages
- 36 pages
- publisher
- [Publisher information missing]
- language
- English
- LU publication?
- yes
- id
- 04d356a0-7740-4f12-9804-123adcf73336 (old id 530517)
- date added to LUP
- 2007-09-07 09:57:06
- date last changed
- 2016-08-16 15:26:26
@techreport{04d356a0-7740-4f12-9804-123adcf73336, abstract = {In the present paper an iterative time-reversal algorithm, that retrofocuses an<br/><br> acoustic wave ﬁeld to its controllable part is established. For a ﬁxed temporal<br/><br> support, i.e., transducer excitation time, the algorithm generates an optimal<br/><br> retrofocusing in the least-squares sense. Thus the iterative time-reversal algorithm<br/><br> reduces the temporal support of the excitation from the requirement of<br/><br> negligible remaining energy to the requirement of controllability. The timereversal<br/><br> retrofocusing is analyzed from a boundary control perspective where<br/><br> time reversal is used to steer the acoustic wave ﬁeld towards a desired state.<br/><br> The wave ﬁeld is controlled by transducers located at subsets of the boundary,<br/><br> i.e., the controllable part of the boundary.<br/><br> The time-reversal cavity and time-reversal mirror cases are analyzed. In the<br/><br> cavity case, the transducers generate a locally plane wave in the fundamental<br/><br> mode through a set of ducts. Numerical examples are given to illustrate the<br/><br> convergence of the iterative time-reversal algorithm. In the mirror case, a<br/><br> homogeneous half space is considered. For this case the analytic expression<br/><br> for the retrofocused wave ﬁeld is given for ﬁnite temporal support. It is shown<br/><br> that the mirror case does not have the same degree of steering as the cavity<br/><br> case. It is also shown that the pressure can be perfectly retrofocused for<br/><br> inﬁnite temporal support. Two examples are given that indicate that the<br/><br> inﬂuence of the evanescent part of the wave ﬁeld is small.}, author = {Jonsson, B Lars G and Gustafsson, Mats and Weston, Vaughan H. and de Hoop, Maarten V.}, institution = {[Publisher information missing]}, language = {eng}, pages = {36}, series = {Technical Report LUTEDX/(TEAT-7115)/1-36/(2003)}, title = {Retrofocusing of Acoustic Wave Fields by Iterated Time Reversal}, volume = {TEAT-7115}, year = {2003}, }