A funeral service will be held in the MIT Chapel on Thursday, March 11 at 2:30pm for Mï¿½rten Landahl of Waltham, a professor of aeronautics and astronautics, who died suddenly on March 4. He was 71.
Professor Landahl was internationally known for his work on unsteady flows, wave motion and hydrodynamic instability, and transition to turbulence, which arises when air or another moving fluid comes in contact with any kind of surface. Shortly before his death, he completed research on the basic initial theoretical problem of how a 3-D initial disturbance within a shear flow evolves over time. He felt certain his work would form a new fundamental approach to the transition problem (tackled by many in the past 100 years) as opposed to the classical Orr-Summerfield equation, and he had planned further research on completing the asymptotic long-time evolution of a 3-D disturbance in a parallel shear flow. He then planned to use this work as the basis for a new transition theory as well as a new turbulence model.
Professor Landahl's early monograph, Unsteady Transonic Flow (Pergamon Press, 1959) was awarded the status of a classic physics text when it was reprinted in paperback in 1995, and a text he co-authored with Holt Ashley, Aerodynamics of Wings and Bodies (Addison-Wesley, 1965), was one of the first to bring in the use of numerical techniques for wing loading predictions. His recent book, Turbulence and Random Processes in Fluid Mechanics (Cambridge University Press, 1986 and 1992), co-authored with E. Mollo-Christensen, was widely recognized as a clear introduction to this difficult subject.
Born on August 6, 1927 in Vasternora, Sweden, Professor Landahl attended the Royal Institute of Technology in Stockholm and earned three degrees: the Civilingenjor in 1951, the Teknologie Licentiat in 1953 and a doctorate in 1959. He worked at MIT from 1954-56 as a research engineer in the Aeroelastic Laboratory and was then a research scientist for the Aeronautical Research Institute of Sweden from 1956-60 before returning to MIT as an associate professor. In 1963 he was promoted to full professor at MIT and in 1967 he was also named a full professor of mechanics at the Royal Institute of Technology.
Professor Landahl, whose hobbies included studying many other fields of science as well as skiing and gliding, won a number of honors and awards. He was elected to the Royal Swedish Academy of Engineering Sciences and the Royal Academy of Science in Sweden. In the United States, he was a Fellow of the American Physical Society and of the American Institute of Aeronautics and Astronautics, and a member of the American Association for the Advancement of Science.
He received the Thulin Gold Medal from the Swedish Aeronautical Society in Stockholm for contributions in the field of aeronautics, was selected as the Ludwig Prandtl Memorial Lecturer (one of the highest honors in fluid mechanics) in Germany in 1983, and received the Daniel and Florence Guggenheim Award from the International Council of Aeronautical Sciences in 1990. Professor Landahl also held patents for separation of heavy atoms from light atoms, and for separation of uranium hexafluoride.
He is survived by his wife, Christine M.; two stepsons, Peder and Christian Soderstrom; a son, Gustaf; two daughters, Ingrid and Elisabeth Landahl; sisters Annalisa Landahl and Britta Schandler Landahl; a niece, Anna Karin Schandler; and seven grandchildren. He will be buried in Sweden.
A version of this article appeared in the March 10, 1999 issue of MIT Tech Talk (Volume 43, Number 22).