Upheaval, instability (10)
I believe the answer is:
turbulence
I believe this clue is a double definition.
'upheaval' is the first definition.
(I know that upheaval can be written as turbulence)
'instability' is the second definition.
(I have seen 'Airy instability' mean 'turbulence' so perhaps 'instability' could also mean 'turbulence')
(Other definitions for turbulence that I've seen before include "Disorderly or confused state" , "Disorder, instability" , "Airy instability" , "Disturbed state" , "Disorder in flow" .)