LAUSR

Periodic structures have various applications in wave systems, such as atomic crystals, photonic crystals, and phononic crystals. Here, we extend the related physics from wave systems to convection-diffusion systems and propose the concept of thermal convection-diffusion crystals, referring to a periodic porous medium with moving fluid. Phenomenally speaking, only the temperature profiles with allowed frequencies can propagate stably in a thermal convection-diffusion crystal, and those with forbidden frequencies try to change their frequencies for stable propagation. As an application of thermal convection-diffusion crystals, we further design a thermal frequency modulator to manipulate wave-like temperature profiles. These results broaden the application scope of periodic structures in convection-diffusion systems and enlighten further development of thermal management and thermal metamaterials with thermal convection-diffusion crystals.