He joined the faculty at Penn and was a popular figure on campus, always sporting a bow tie and pipe. His field of expertise, though, was anything but sporty. He specialized in ballistocardiography, a way of measuring and mapping the pressure and flow of blood into the great vessels of the heart with each heartbeat.
His mathematical studies had many applications, including in the treatment of hypertension, on vein collapse, and in how to measure the efficacy of cardiopulmonary resuscitation. He wrote widely, but his textbook "Blood in Motion" was a classic in cardiovascular science.
Dr. Noordergraaf and other scholars called an international meeting in Valley Forge in April 1975. The gathering formed the basis for the Cardiovascular System Dynamics Society inaugurated in 1976.
The papers presented at the conference, and edited by Dr. Noordergraaf and two colleagues, were published by MIT Press as Cardiovascular System Dynamics, considered a standard work on the subject.
An adventurous traveler, Dr. Noordergraaf's research took him across the globe. He also spent vacations in Maine, sailing. When at home in Haverford, he immersed himself in repair projects.
He was a master in the preparation of pannekoeken, Dutch flapjacks, which were the highlight of Saturday night dinners, his family said. "You eat them with powdered sugar, or with syrup or applesauce," said his daughter. "Not low-calorie, but delicious." He also enjoyed playing dominoes, and was a lifelong member of the Presbyterian Church.
He married Geertruida Noordergraaf. The two divorced; she died in 2013 in the Netherlands.
In addition to his daughter, he is survived by sons Gerrit Jan Noordergraaf and Alexander Noordergraaf; another daughter, Jeske Noordergraaf; 10 grandchildren; and many nieces and nephews.
A celebration of Dr. Noordergraaf's life will be held Saturday, May 31, at the Bringhurst Funeral Home at West Laurel Hill Cemetery, 225 Belmont Ave., Bala Cynwyd. A viewing at 9 a.m. will be followed by a service at 10, and a reception. Burial is private.
Donations may be made to the First Presbyterian Church in Philadelphia, 201 S. 21st St., Philadelphia, Pa. 19103, or via www.fpcphila.org.