In a new twist, a team of researchers from the U.S. Naval Research Laboratory and the University of Texas at Austin has applied to acoustic waves the concept of "scattering cancellation," which has long been used to systematically cancel the dominant scattering modes of electromagnetic waves off objects.
The work provides fundamental new tools to control acoustic scattering and should improve the ability to make acoustic measurements in the laboratory. It is described this week in the Journal of Applied Physics, from AIP Publishing.
"Scattering" occurs when an object has material properties different than those of the medium surrounding it, such as air or water, and its "mode" is characterized by the way waves bounce off of it. By applying a coating with the appropriate material properties, electromagnetic scattering modes can be cancelled -- a process known as "scattering cancellation."
It turns out that this applies equally well to other types of waves, such as acoustic waves. As the team reports this week, the principles of scattering aren't limited to electromagnetic waves but are a fundamental feature of how any type of wave interacts with its environment.
(Score: 2) by frojack on Saturday October 31 2015, @08:18PM
I can see why the Navy would want a sonar defeating coatings.
What is interesting here is that hydrophone enclosures cabling significantly interfere with what they were trying to listen to.
Coating those components can drastically reduce this.
No, you are mistaken. I've always had this sig.
(Score: 2) by Dr Spin on Saturday October 31 2015, @10:43PM
Fixing coatings to surfaces?
How exactly is this different from sticking egg trays and foam rubber pyramids on the walls and ceiling, as we used to do when I worked in recording studios, 30 years ago?
Warning: Opening your mouth may invalidate your brain!
(Score: 1) by dak664 on Sunday November 01 2015, @05:52PM
From TFA,
"The key significance of this work? It's the "formulation of a more general approach using acoustic scattering cancellation for complex, odd-shaped objects," said Guild. Previously, the approach was considered only for relatively simple shapes such as solid spheres and cylinders."
Apparently, stimulated by the desire to study complex, odd-shaped acoustic hydrophones :)
(Score: 1) by anubi on Sunday November 01 2015, @07:03AM
Is this like the optical equivalent of "flat black" paint?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]