Look at the following sentence:
Her family was happy when she returned home
It is clear that "when she returned home" is a dependent clause because it starts with "when" and has a subject and a verb. But I am doubtful if it is an adverbial clause or a noun clause. As far as I know, it could be both of them if you think of it from different views:
First, We could consider it an adverbial clause as it starts with conjunction "when" and describes the verb "was". It gives information about the time when they were happy so it is basically an adverb.
On the other hand, It looks as if "when she returned home" is a noun clause which acts as an adjective complement.
I don't know which one is correct. Or may be both of them are correct at the same time?