Cathleen Synge Morawetz
Mathematics professor
Cathleen Synge Morawetz, mathematician. Born: 5 May, 1923 intoronto, Canada. Died: 8 August, 2017 in New York City, New York, aged 94
Cathleen Synge Morawetz, a mathematician whose theorems often found use in solving real-world engineering problems, has died at the age of 94
Her death was reported by New York University, where she had been a professor. Much of Morawetz’s research centered on equations that describe the motion of fluids and waves — in water, sound, light and vibrating solids. One of her first notable papers helped explain the flow of air around planes flying close to the speed of sound.
Although the aircraft itself does not break the sound barrier, she found, some of the air rushing around the curves of its wings goes supersonic. Below the speed of sound, air flows in a fundamentally different manner than at super- sonic speeds, and the mix of the two speeds — called transonic flight — produces shock waves that slow the aircraft.
Wings can be designed so that transonic airflow remains smooth at certain speeds without generating shock waves. But Morawetz’s work demonstrated that such shock-free wings do not work in the real world. The slightest perturbation — an imperfection in the shape, a tilt in the angle of the wing, a gust of wind — disrupts the smooth flow.
With that insight, aerospace engineers now design wings to minimise shocks rather than trying to eliminate them.
In later work, Morawetz studied the scattering of waves off objects. She invented a method to prove what is known as the Morawetz inequality, which describes the maximum amount of wave energy near an object at a given time. It proves that wave energy scatters rather than lingering near the object indefinitely.
Cathleen Synge was born 5 May, 1923, in Toronto, the daughter of Irish immigrants. Her father, John Lighton Synge, was a physicist and mathematician known for research that used a geometric approach to study Einstein’s theory of general relativity. Her mother, the former Elizabeth Eleanor Mabel Allen, had been a maths major in college but dropped out when she married. Morawetz credited her mother with encouraging her to have a career.
She earned a bachelor’s degree in mathematics at the University of Toronto in 1945, the same year she married Herbert Morawetz, a polymer chemist.
In addition to her husband, Morawetz is survived by three daughters, Pegeen Rubinstein, Lida Jeck and Nancy Morawetz; a son, John; a sister, Isabel Seddon; six grandchildren; three great-grandchildren;andfourstep-grandchildren. © New York Times 2017. Distributed by NYT Syndication Service