1) Engineering: transient oscillation, unsteady oscillation
2) Mathematics: unsteady vibrations
3) Metallurgy: unsteady oscillations, unsteady-state oscillations
4) Telecommunications: unstable oscillation
5) Astronautics: unstable oscillations
6) Geophysics: transient oscillations
Универсальный русско-английский словарь. Академик.ру. 2011.