Compressible flows refer to the behavior of fluids when they are moving at speeds close to or exceeding the speed of sound. This research area focuses on studying the changes in pressure, temperature, and density of gases and liquids as they flow through various systems or environments. Compressible flows are commonly found in aerospace engineering, gas dynamics, and combustion systems. Researchers in this field use principles of thermodynamics, fluid dynamics, and aerodynamics to analyze and predict the behavior of compressible flows in order to design efficient and safe systems.