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Daniel Bershader, aerophysics pioneer, dies at 72
STANFORD -- Daniel Bershader, an aerophysicist whose studies of the turbulent flow of gases led to important knowledge about the physics of supersonic flight and the entry of space vehicles into planetary atmospheres, died at his Stanford home Tuesday, May 30, after a brief illness from complications due to chronic peptic ulcer disease.
Bershader, 72, was a professor emeritus of aeronautics and astronautics at Stanford University who had been recalled to active duty for the 1994-95 academic year. He was director of the Aero-Astro Shock Tube Laboratory and of the Summer Faculty Fellowship Program sponsored by Stanford, the National Aeronautics and Space Administration and the American Society for Engineering Education.
As director of that fellowship program since 1972, he served as host to scientists and engineers from around the world who came to Stanford for symposia and for hands-on research at the nearby NASA-Ames research laboratories.
Born in New York City on March 14, 1923, Bershader graduated from Brooklyn College in 1942 and went to work in flight test research at Bell Aircraft Corp. During World War II, he was a Navy petty officer involved in research on depth charges for submarines, his son Brian Bershader said.
After the war, he earned a master's degree in physics from Princeton in 1946 and a doctorate from the same institution in 1948. Friends said he was fond of recalling one of his physics professors there, Albert Einstein. Bershader taught at Princeton and the University of Maryland before taking a joint appointment in 1956 as associate professor at Stanford and manager of gas dynamics research at Lockheed. In 1964, he became a full-time member of the Stanford faculty.
As an aerophysicist, Bershader "often said he liked to use aeronautical research as an excuse for doing basic physics," said his friend and colleague Holt Ashley, professor emeritus of aeronautics and astronautics. Ashley said that Bershader used the shock tube laboratory to measure a wide range of phenomena in fluid mechanics. A shock tube works like a miniature wind tunnel, generating a fast-moving shock wave in a mixture of gases.
Among Bershader's first contributions was an investigation of the supersonic boundary layer, the layer of air at the surface of a fast-moving object.
"When he started to do this work in the 1940s and 1950s, it was at a time when we were trying to learn to fly at supersonic speeds," said Michael Tauber, a colleague and former graduate student of Bershader's at Stanford, who recently retired as a research scientist at NASA-Ames.
Tauber said that Bershader's work, beginning with his doctoral thesis at Princeton, provided important knowledge about the generation of drag, noise and heat. By studying how a shock wave compresses gas and raises its temperature, he helped explain the physics of high-speed flight -- in particular, how an aircraft or spacecraft heats up at high speeds in the atmosphere of Earth and other planets.
Among other applications, Bershader's research was used to help design the space probes that were sent into the atmospheres of Mars and Venus.
In some of his most recent work, Ashley said, Bershader and his colleagues had pioneered optical techniques to create three-dimensional photographs of vortices, swirls of gases moved along at high speeds within the shock tube. The photos, which Ashley described as "beautiful," also can give important information about the action of gases moving at high speeds and high temperatures -- for example, to study combustion inside a jet engine.
In recent years, Bershader also used the shock tube laboratory to study the sources of noise generated by helicopter blades. A lover of classical music, he had an avid interest in noise pollution and developed an interdisciplinary course on the topic. He was instrumental in the campaign to install the fabric banners that serve as noise baffles in the dining hall of Stanford's faculty club.
Bershader was "a stalwart faculty leader and prominent figure in the early days of the academic senate," said Richard Lyman, president emeritus. "He could think in terms of his institution as well as about sustaining his own field."
In addition to chairing the fourth Faculty Senate in 1971-72, Bershader served on a number of university committees and special task forces over the years. During his year as Senate chair, he was an outspoken critic of disruptions of campus events, including the Faculty senate, and urged others to condemn the disruptions.
He was also a leader in his scientific field, serving as head of the fluid dynamics division of the American Physical Society. "By his leadership, and by organizing research conferences, he contributed more to the profession than almost anyone," Ashley said. He said Bershader's example led others to study the physical basis of fluid mechanics. Bershader also served as the pillar of a weekly lunchtime discussion group on fluid mechanics that brought together people from many disciplines at Stanford and outside the university.
In 1987, Bershader led the committee that drafted the American Physical Society's statement on professional ethics in physics. In the early 1980s, he was involved in distributing a letter signed by many prominent American physicists, criticizing the scientific underpinnings of the Reagan administration's Star Wars space- based defense program.
Bershader was an avid tennis player and an accomplished pianist. For years, he ushered at the San Francisco opera and symphony, and he played in local faculty trios during his early years at Stanford.
His colleagues recall Bershader especially for his even-handed diplomacy. "I don't believe I've ever seen him angry," Ashley said. Vladim Matte, who worked with Bershader as a science and engineering research associate, said, "In 35 years, I have never seen a man who was so much a gentleman in the true sense of the word."
Bershader is survived by two sons, Brian of Palo Alto and Lee of Fremont, and stepsisters Alice Friedman of Rochester, N.Y. and Betty Freeman of New York City. Memorial services are scheduled for 4 p.m. Friday, June 9, at the Stanford Faculty Club. In lieu of flowers, the family requests contributions to the Jewish Community Federation of San Francisco or the Museum Society of the DeYoung Museum of San Francisco.
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