That is called a "glissando".

The pianist performed a beautiful glissando, smoothly sliding their fingers across the keys in a seamless cascade of notes.

A glissando is a musical scalelike passage, and could be termed a melodic phrase.

Glissando is a musical term. It means a rapid sequence of rising or falling notes.

In Classical music rapidly playing a series of notes which is discretely audible is called a glissando. This can be done either on a piano or a harp.