Transient Magnetohydrodynamic Flow in an Annular Channel M. Narasimhan Indiana University Mathematics Journal 1965 text pdf 10.1512/iumj.1965.14.14025 10.1512/iumj.1965.14.14025 en Indiana Univ. Math. J. 14 (1965) 353 - 363 state-of-the-art mathematics http://iumj.org/access/