Sending out sounds to shove and shape air, water and fire
We usually experience sound as information from the world around us, an auditory analog of light. It’s easy to forget that hearing is part of a largely mechanical process, where energy is being passed through various materials, like the air, or your apartment ceiling, by knocking molecules into each other. There’s always some movement in these molecules, but when they’re pushed as a group at the right timing, the vibrations can be perceived by our ears and brains as sound. However, these same pressure-waves can be used for more than the enjoyment of our ears, with applications ranging from cleaning windows to possibly mitigating the damage from tsunamis.
Pushing air particles
Car manufacturer McLaren is looking to use sound waves to clean their cars’ windshields. The concept, which as been used in fighter jet canopies as well, uses extremely high-pitched sound waves to create a vibrating layer of particles across the front of the windshield. These vibrating particles essentially shake everything from water to dirt loose, before they can accumulate on the glass. The biggest advantage of using sound like this is that a small ultra-sonic transducer in the corner of the windshield can replace bulkier mechanical devices like windshield wipers, which hurt the vehicle’s aerodynamic profile.
From beyond-squeaky to a low-pitched hum, students at George Mason University developed a sound-based fire extinguisher. The hand-held device pumps out low-frequency sound waves that essentially push the oxygen away from any burning fuel, which prevents further combustion. The inventors originally thought of putting out grease fires on stove-tops, but these devices may be useful in more exotic locations as well, like the International Space Station. Spraying fluids or foam in microgravity is hard to control, but sound waves made of air are easier to control, and leave no mess to clean up afterwards.
Sending waves into the water
On a much larger scale, researchers are proposing an idea to reduce the impact of tsunamis with large, carefully-timed sound waves. No device exists at this point, but the hypothesis is that an acoustic-gravity wave could be broadcast at an incoming tsunami and spread the roiling water out laterally, so that it would not hit the shore with as much force, and water, in one place.
Acoustic-gravity waves operate on many of the same principles as sound waves in the air, but the each wave can travel very quickly for huge distances as it transmits energy back and forth from the sea floor to the water’s surface. These waves are also created by Earthquakes and tsunamis, and may play a role in early detection systems, but this new model would have synthetic waves disrupt and redistribute some of the energy from incoming water, lessening the impact of the tsunami.
Source: Sound waves could take a tsunami down a few notches by Emily Conover, ScienceNews