Oak barrels are commonly used to age red wine but it is much more rarely used with white wine. Chardonnay seems to spend some time in oak and V9 also talks about ageing pinot noir in oak. Can oak ageing be good for mead? One must try it in order to be able to answer.
Dust or small chunks (even used staves) can be purchased. This alternative is much less expensive and troublesome than a barrel (figure 22) and its contribution to the taste is quite similar. It is therefore not necessary to invest in an oak barrel to carry experiments of oak flavoring.
A used barrel may need months to give oak flavor to the mead but a new barrel or oak chunks immerged in the mead may need as little as a few days or weeks to communicate their flavor. It is therefore necessary to taste test often. The oak flavor will dim to some extent [V9], so if oakiness is too strong, age and see if it is enough. If it is not, blend with a batch that do not receive oak (see blending in Recipe).
In MLD 905, the oak is advised to improve the nose (by A. Kemp) and according to N. Kanous it improves the complexity of mead.
References: Singleton in B3 (chapter 12) and in V4 (chapter 12), chapter 14 of V9.