Researchers designed an underwater acoustic ground cloak by engineering material with properties not typically found in nature, rendering an object invisible
Cloaking devices play a pivotal role in many sci-fi television programs. Scientists are now working to take this technology from the dramatic realm of science fiction and make it real. Amanda D. Hanford, at Pennsylvania State University, is taking the introductory steps to make acoustic ground cloaks. These materials redirect approaching waves around an object without scattering the wave energy, concealing the object from the sound waves.
During the 175th Meeting of the Acoustical Society of America, being held May 7-11, 2018, in Minneapolis, Minnesota, Hanford will describe the physics behind an underwater acoustic shield designed in her lab.
Hanford and her team set out to engineer a metamaterial that can allow the sound waves to bend around the object as if it were not there. Metamaterials commonly exhibit extraordinary properties not found in nature, like negative density. To work, the unit cell — the smallest component of the metamaterial — must be smaller than the acoustic wavelength in the study.
“These materials sound like a totally abstract concept, but the math is showing us that these properties are possible,” Hanford said. “So, we are working to open the floodgates to see what we can create with these materials.”
To date, most acoustic metamaterials have been designed to deflect sound waves in air. Hanford decided to take this work one step further and accept the scientific challenge of trying the same feat underwater. Acoustic cloaking underwater is more complicated because water is denser and less compressible than air. These factors limit engineering options.
After multiple attempts, the team designed a 3-foot-tall pyramid out of perforated steel plates. They then placed the structure on the floor of a large underwater research tank. Inside the tank, a source hydrophone produced acoustic waves between 7,000 Hz and 12,000 Hz, and several receiver hydrophones around the tank monitored reflected acoustic waves.
The wave reflected from the metamaterial matched the phase of the reflected wave from the surface. Additionally, the amplitude of the reflected wave from the cloaked object decreased slightly. These results demonstrate that this material could make an object appear invisible to underwater instruments like sonar.
Using linear coordinate transformation, the researchers were able to map the flat surface of the bottom of the tank and determined that space was compressed into two triangular cloaking regions consisting of the engineered metamaterial.
These results show potential to contribute to real-world applications, such as acoustic materials to dampen sound and appear invisible underwater.
Learn more: Cloaking devices — it’s not just ‘Star Trek’ anymore
The Latest on: Cloaking device
[google_news title=”” keyword=”cloaking device” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Cloaking device
- The Finals fans say changes to revives hot take would ‘break the game’on April 26, 2024 at 4:52 am
A hot take proposing gameplay changes to revives in The Finals has fans collectively screaming it would 'break the game'.
- The Finals hyped ‘very cool’ update could be this teased new modeon April 25, 2024 at 5:29 am
The Finals developer has said that the next update will add 'something very cool' and it could be a previously teased new game mode.
- Realization of an ideal omnidirectional invisibility cloak in free spaceon April 22, 2024 at 10:00 am
A team led by Prof. Dexin Ye and Prof. Hongsheng Chen from Zhejiang University, and Prof. Yu Luo from Nanyang Technological University conducted research on the practical implementation of ...
- UK data watchdog questions how private Google's Privacy Sandbox ison April 22, 2024 at 4:13 am
Just two months ago, the UK's Competition and Markets Authority, which has been overseeing the Privacy Sandbox effort based on antitrust concerns and commitments from Google to play nice, published an ...
- The Finals’ new update stuns Light class players the wrong wayon April 17, 2024 at 4:14 am
Start switching up your tactics in The Finals, as the latest The Finals update on PS5 and Xbox tackles Light players with these nerfs.
- The Finals Update 2.5.0 for Version 1.000.026 Brings Balance Changes This April 17on April 17, 2024 at 2:38 am
Embark Studios has released The Finals update 2.5.0 (PS5 update version 1.000.026) for several balance changes. Here is more info.
- 8 Coolest Starships From Star Trek: The Next Generationon April 16, 2024 at 5:30 am
These are some of the coolest-looking ships that stand out the most in Star Trek: The Next Generation. The Galor-class cruiser introduced the brutal might of the Cardassian Union, setting itself apart ...
- Scientists solved the 70-year-old mystery of an insect's invisibility coat that can manipulate lighton April 15, 2024 at 10:13 am
A team of researchers created the world's first synthetic brochosomes in a huge step towards invisibility cloaking technology.
- 12 Star Trek Female Villains Ranked, Worst To Beston April 13, 2024 at 1:00 pm
While some female villains like the Borg Queen excel, others like Seska from Voyager fall short of their potential. While the canon of ...
via Bing News