Leaky systems have restricted engineers in terms of designing thermal casting devices which majorly rely on interplay between sound waves and temperature oscillations. However, researchers at Purdue and the University of Notre Dame have recently shown for the first time in history that thermoacoustic could to radically occur not only in liquids but in solids as well. This technology is expected to particularly be useful in harsh environments in outer spaces where the variation of temperature is high as well as in those application areas where system failure could endanger the entire mission.
Thermoacoustic have been well studied phenomenon in fluids for over centuries. Applying heat to a fluid cause spontaneous generation of sound waves propagating in the fluid itself and this results in singing pipes or thermoacoustic machines. Fluids have been historically used in these systems but building something in order to contain the fluids as well as preventing the leak is tedious and this has led researchers to consider a replacement for a fluid by solids.
As the properties of solids are much more controllable than the properties of liquid, solids make a potentially better Suited medium for applications. But for this, it was essential that this phenomenon could be verified and therefore the researchers develop the theoretical model demonstrating that a rod of metal can exhibit mechanical vibrations which are self-sustained, if the temperature gradient is applied to the segments of the word periodically. This in turn balanced the unwanted mechanical energy dissipation, and demonstrated that just like fluids, solids also contract when they cool down and expand when the heat up. Moreover if the solids contract-less on Cooling and expands more on hitting than the resulting motion will increase over time.