hr. J. fferrr Mass Transfer. Vol. 31, No. 12, pp. 2399-2400, 1988

Pergamon Press plc.Printed in Great Britain

Professor Benjamin Gebhart
on his 65th birthday

Benjamin Gebhart
celebrated
his 65thbirthday earlier this year. On this occasion, it is apleasure to remember and honor his many achievements in the field of heat transfer.
Professor Gebhart was born in Cincinnati on 2 July
1923 and was raised in southwestern
Ohio. After one
year as an apprentice tool maker in Detroit, he served
as a Marine in World War II, returning to undergraduate work at the University of Michigan in Fall
1945. He obtained a Bachelor’s degree in MechanicalEngineeringin 1948 and a Master’s degree in 1950
from Michigan. He then joined Cornell University,
receiving his Ph.D. degree in Mechanical Engineeringin 1954. He stayed at Cornell University as a memberof the faculty of MechanicalEngineeringtill 1975,
when he joined the State University of New Yorkat Buffalo as Leading Professor and Chairman.
Heaccepted his present position of Samuel Landis Gabel
Professor of Mechanical Engineering at the Universityof Pennsylvania in 1980.
Professor Gebhart has been an outstanding
and avery active researcher over the past three decades. He
has contributed
more than 150 papers on various
aspects of heat transfer and the associated fluid flow.
He is an internationallyrecognized authority in areas
such as natural convection, mixed convection, opticalinstrumentation,
instability,
radiative
transport
inenclosures,convective
flows in the environment,
transport
in cold water, ice melting in cold water,transition and turbulence, combined heat and masstransfer, transient convection
and buoyant jets. His
PROFESWR“NT31:12-*2399

first book Heat Transfer was published in 1961, withan extensively revised version appearing in 1971. This
book had a major impact on the analysis of convective
flows and became an important reference for researchin this area since it laid down the physical and fundamental basis for studying thermal convection. Morerecently, Professor Gebhart has published, with threeco-authors,a substantialreference
work entitled
Buoyancy-induced Flows and Transport. This bookbrings out the essential aspects of these flows alongwith the extensive work done on various flow configurations.
Throughout
his distinguishedcareer, carefullyplanned, precision experimental work has been a hallmark of his research. He developed and perfectedinterferometrictechniques for non-intrusive
studiesof buoyancy-driven
plume flows and wall boundary
layers. In a series of truly elegant experiments, he andhis students obtainedinterferometricphotographs
which documented
the selective amplificationof disturbances in natural convection flows. These experiments unequivocallyverified the results of his concurrent
theoreticalstudiesof the disturbance
amplification
characteristics
in such flows based onstability theory. More recently, he has turned his
experimental energy to buoyancy driven flows in cold
water which exhibit complex buoyancy-force
reversals. His innovative use of flow visualization and hot
film anemometry techniques in laboratory studies has
made possible a clearer understandingof the complicated transport mechanisms in flows of this type.

2400

Y. JALUKIA el al.

Never being timid about venturing from the laboratory, he also has undertaken
an expedition
to thenorth polar ice pack, where he made experimental
measurementsof the temperaturefields in sea water
near the ice for subsequent comparison
with theoretical predictions. (Avoiding the polar bears was justanother experimental
problem to overcome.)
Professor Gebhart’s perspective on experimental work isperhaps best reflected in some advice he once gave a
graduate student regarding some unexpected experimental results: “When nature talks, you have tolisten.” Experimental
work is a conversation
withnature. One can learn the most from the conversation
by asking the right questions in a precise manner andby interpreting the response with an open mind.
A special mention must be made of the tremendous
physical insight that Professor Gebhart brings to hisresearch. His abilities to dissect a complex physicalprocess into its basic elements and to physically interpret the sometimes abstract results of transport analyses in a clear and insightful manner have helped
advance our understandingof the science of heattransfer. Another distinguishing
characteristicof his
research is the high standard of quality that he has set
for himself and expects from the students who haveworked with him over the years. His papers are wellknown for the care with which the analysis or experiment is carried out and for the fundamental
aspects
often researched in these studies. The result has been
many widely cited papers in journals such as the Jouvnal of Fluid Mechanics.
Professor Gebhart has received accolades from hisstudents, past and present, for being an outstanding
teacher, who brings his deep physical understanding
and insight to his class. He has the rare gift of putting
the intricate mechanisms that govern thermal transport into simple terms so that a student can follow
the basic features of the process without getting lostin the complexities of the mathematics.
He has guided
more than 28 students for their Ph.D. thesis. Of these
11 are in academia and most of the others in industrial
research positions, carrying on the research and teaching traditions set by their mentor.
The work done by Professor Gebhart has had quite
an impact on the research in thermal sciences throughout the world. He has himself been involved with theefforts in many countries such as China, France andNorway. He participatedin NORSEX
V, a Norwegian Research Expedition into the Arctic Ice Packin 1978, to carry out transport and thermodynamicsmeasurements.
He has held AssociatedProfessor
appointments
in France and has visited China several
times to lecture on heat transfer and to evaluate theprogram at Nanjing Institute of Technology. He has
also given invited lectures at a NATO Advanced Study
Institute on Natural Convectionin Turkey. He has
contributed many review papers on different topics ofinterest to him over the years in many different journals. In recognition for his contributions
to heat transfer, he was named the ASME Freeman Scholar of
1978 and was awarded the prestigious ASME HeatTransfer Division Memorial Award in 1972. He wasthe NAVSEA Research Chair Professor at the Naval
Postgraduate
School, Monterey,
in 198&81. He is
also on the Editorial Advisory Board of many journals
such as International Journal of Heat and Mass Transfer, Numerical Heat Transfer, International Communications in Heat and Mass Tramfer, Heat Transfer-Japanese
Research and Heat Transfer-Soviet
Research.
An important element in Professor Gebhart’s life is
his love for nature. Besides carrying on research inmany areas related to our environment,
he has beendeveloping a large 340 acre nature preserve in upstate
New York. He has also worked ceaselessly to support
the preservationof the forest and the animal life inthis region. He is extremely knowledgeable on naturalprocesses and has carried out detailed experimental
investigations
on the flow and transport
stemmingfrom these, including the flow over corn fields andtransport in arctic regions.
On the occasion of his 65th birthday, it is indeed apleasure for his students, friends and colleagues, alongwith the editors of this journal, to honor his outstanding and remarkable achievements
and to wish
him success and happiness for many years to come.
Y. JALURIA
R. L. MAHAJAN
W. J. MINKOWYCZV. P. CAREY
J. C. MOLLENDORF
N. LIORJ. P. HARTNETT