Forrest M. Holly Jr.: The Pursuit of Excellence in Hydraulics and Beyond

It is hard to imagine a more accomplished yet unassuming individual than the late Forrest M. Holly Jr. His many important contributions to the burgeoning field of computational hydraulics are unmistakable, while he conducted his personal interactions with grace and ease of manner. He had a deep interest in problem solving, and truly enjoyed the challenge of getting the right answer for the right reason. His lasting legacy comes from outstanding mentoring of students and many insightful interactions with colleagues. This talk uses the technical note “Invalidity of the Preissmann Scheme for Transcritical Flow” written by Ehab Meselhe, who was then a Ph.D. student, and his advisor Forrest, to highlight an excellent example of student mentoring in a scientifically rigorous fashion. This important publication, which was awarded as the “Outstanding Technical Note” by the ASCE J. of Hydraulic Engineering in 1999, aimed to advance our understanding of fundamental computational hydraulic issues, while encouraging the student to attain an advanced level of intellectual achievement. This paper presented a stability analysis showing that the 1-D Preissmann double-sweep channel routing scheme is incapable of accurately and reliably solving transcritical flow problems. The importance of this result springs from the fact that in hydrological networks trans-critical flow is an unavoidable consequence of breaks in slope, changes in flow resistance, or abrupt changes in cross-section. The impact of this paper was immediate, with broad applicability as it demonstrated that computational models of these networks based on the 1-D Preissmann double-sweep scheme cannot in general be expected to function properly if transcritical flow occurs, and spurred the quest for improved methods. In addition to deep contributions to computational hydraulics, Forrest had many other passions. These included music, clocks, aviation, fitness, and astronomy, all of which he seemed to approach with equal vigor. This presentation concludes with some observations regarding how all of these interests coincided in one individual, and provide an example of a life well lived in the pursuit of excellence.