An inlet cone, as far as I know, is a component on an engine to guide the intake air smoothly into the compressor stage of a jet turbofan engine, it performs as a fairing(aerodynamic covering)of the axis on which the intake fan is installed, to improve the aerodynamic efficiency. *The engines are all on subsonic airliners.
However, I found that on some modern high bypass turbofan engines, this cone(fairing)is in a pointed, sharp, conical design that seems to only appear on supersonic aircrafts, as a rounded design is optimized for subsonic flight. For example, in the images below:
While on some turbofan engines, this cone(fairing)is in a smooth, rounded design, very much like it would have been used on the nose design of the aircraft. For example, the engines on a MD-80: Why do those modern engines have this conical sharp intake cone(or fairing)design? Is this because of the air acceleration above the speed of sound when intaking air at cruising speeds?