Convective instability of a rotating layer of ferromagnetic fluid
The instability of a hot horizontal layer of ferromagnetic fluid rotating about a vertical axis has been investigated when the Prandtl number \(P<1\). Earlier it was shown that for \(P>1\) the overstability cannot occur. In this paper the convective and overstable marginal states have been investigated separately for \(P<1\) and it is found that though convective marginal state is possible for all \(\alpha\), the non- dimensional wave number, and N the Taylor number, the overstability is possible only if \(N>(1+P)\pi^ 4/(1-P)\) and in case the condition is satisfied, overstability is possible for all those values of \(\alpha\) which satisfy \(\alpha^ 2<[N(1-P)\pi^ 2/(1+P)]^{1/3}-\pi^ 2\). If \(R_ c^{(con)}\) and \(R_ c^{(o.s.)}\) are the critical values of the convective and the overstable marginal states, respectively, then it is also found that \(R_ c^{(con)}<R_ c^{(o.s.)}\) provided N is not sufficiently large.
scientific article; zbMATH DE number 3995291