Rotary machines are devices that use circular motion to perform work. They convert energy into mechanical power, often found in engines, turbines, and compressors. These machines operate on the principle of rotation, which allows them to efficiently transfer energy and perform tasks like pumping fluids or generating electricity. Common examples of rotary machines include internal combustion engines, which power vehicles, and wind turbines, which harness wind energy to produce electricity. Their design often includes components like shafts and bearings that facilitate smooth rotation, making them essential in various industrial and commercial applications.