Caltech Mourns the Passing of Professor Allan Acosta, 1924-2020

Allan Acosta, Caltech’s Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering, Emeritus, who spent 50 years at Caltech and helped launch the Institute’s present day mechanical engineering option, passed away on May 18, 2020. He was 95 years old.

Acosta earned his bachelor’s, master’s, and doctoral degrees at Caltech, in 1945, ’49, and ’52 respectively, and was a faculty member at the Institute in the Division of Engineering and Applied Science from 1954 until his retirement in 1993.

He was born in 1924 in Anaheim, California. Shortly before he graduated from high school, the United States entered World War II, so Acosta enlisted in the Navy. Through the V-12 Navy College Training Program, in which the Navy paid college tuition for engineering students who were expected to become officers at the end of the program, Acosta enrolled at Caltech in 1943. After graduating with a degree in mechanical engineering in 1945, Acosta was sent by the Navy to midshipmen’s school at the University of Notre Dame, and then joined an Army-Navy task force at Bikini Atoll, where he witnessed one of the 23 nuclear tests that were conducted in that area following World War II.

In 1946, Acosta returned to Caltech, where he got a job in the Hydraulic Machinery Laboratory. There, he tested new water pumps while taking graduate classes in mechanical engineering. After earning his doctoral degree, he accepted a position as an assistant professor at the Institute in 1954.

As a newly minted faculty member, he oversaw the management of the Hydraulic Machinery Laboratory, which provided researchers with a unique collection of tools for studying the fluid mechanics that govern how aircraft move through air (a fluid) and also how the fluids that propel aircraft (such as jet fuel) move through engines. He was renowned for his contributions to the fluid mechanics of turbomachinery, in particular to rotor dynamics and cavitation.

Acosta taught courses on fluid flow and heat transfer. He worked with a group of faculty with similar interests, including pioneering Caltech mechanical engineer Rolf Sabersky, with whom he published the textbook Fluid Flow: A First Course in Fluid Mechanics in 1963. He was recognized as an exceptional teacher and mentor and was highly influential in shaping the education and training of many generations of students. He was an elected member of the National Academy of Engineering and a Fellow of the American Association for the Advancement of Science.

His interest in fluids and pumps led Acosta to collaborate in the mid-‘70s with Chris Brennen, Richard L. and Dorothy M. Hayman Professor of Mechanical Engineering, Emeritus, on a project for NASA to eliminate the instability caused by a phenomenon known as “pogo” oscillations in the liquid rocket engines used in the space program.

Acosta had a profound influence in defining mechanical engineering at Caltech as one of the founders of the present day mechanical engineering (ME) option. He served as the first executive officer of ME from 1988 to 1993, when he retired.

A full obituary will follow at a later date.