The affix ghañ comes after the root gṝ when the upasarga-s ut and ni are in composition.,
The verb गृ here refers to both the verbs गृ 'to make sound', and गृ 'to swallow'. As उद्गारः समुद्रस्य 'the roaring of the sea'; निगारो देवदत्तस्य 'the swallowing of Devadatta'. But when without these prepositions, we have गरः ।,