In Memoriam Klaus Kirchgässner

Klaus Kirchgässner was born in Mannheim on December 26, 1931, and died in Konstanz on July 9, 2011. He grew up in the small, lovely town of Waldshut, which is located along the Rhine at the extreme south of the Black Forest. With his friends he spoke with enthusiasm about this city, where he did swimming in the Rhine and in the Aare river and where he completed his high-school education (“Gymnasium”). KlausKirchgässner studiedMathematics and Physics at the “Albert-Ludwigs-Universität” of Freiburg, one of the oldest universities in Germany. His pioneering work in hydrodynamic stability began with his doctorate “Beiträge zur hydrodynamischen Stabilitätstheorie”, defended in 1959, under the supervision of Professor Henry Görtler, who was one of the most famous experts in fluid mechanics at this time in Germany and who had been a close collaborator of Ludwig Prandtl for several years. So it was quite a privilege, for Klaus Kirchgässner to give the Ludwig-Prandtl Memorial Lecture entitled “Structure and Dynamics of Nonlinear Surface Waves” at the GAMM Annual Meeting in Leipzig in 1992.