International Journal of Multiphase Flow 122 (2020) 103164

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Remembering Geoff Hewitt

3rd January 1934–18th January 2019

Geoff Hewitt, a towering ﬁgure in multiphase ﬂows, is sadly
no longer with us. When the news of his passing began to ﬁlter
through, I was inundated by tributes to Geoff from all around theworld by email, post, and social media from colleagues, friends,
past PhD students and postdocs, and undergrads who had beentaught by him. They all described their sense of loss, and how
they’d been touched by a man they regarded as being truly oneof-a-kind.
For as long as we’ve known him, Geoff has epitomised excellence, with the kind of glittering career reserved to a select few. He
has made many signiﬁcant contributions to engineering researchand practice over a period of nearly sixty years; indeed, very few
can match Geoff’s contributions in advancing the theory and practice of multiphase ﬂows.
Geoff spent the ﬁrst half of his career at the Harwell laboratoryof UKAEA and was a Division Head. While there, he published over
100 reports/conference papers and over 50 papers in the international literature. He also wrote four books. The emphasis in all thiswork has been on the development of the theory of multiphaseﬂows and heat transfer guided by careful experimental observationin an area where intuition is all too likely to be fallible. He has had
a wide experience of industrial applications through his foundingof the Heat Transfer and Fluid Flow Service at Harwell and throughhis extensive work with industry.
https://doi.org/10.1016/j.ijmultiphaseﬂow.2019.103164
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Geoff then spent the second half of his career as Professor ofChemical Engineering at Imperial College London and brought hisconsiderable experience to revive the whole area of multiphaseﬂow there. He has built experimental rigs that are world-leading intheir ability to handle high-pressure ﬂows. These rigs are by theirnature large; this is because many multiphase ﬂow phenomena arescale-dependent: a small rig can miss essential physics. The sizeof the rigs means that they are expensive and another part of hissuccess has been the way Geoff has raised funds to build and runthem.
While at Imperial, Geoff has published over 100 reports/conference papers and over 110 papers in the international
literature and also co-authored one book. He has supervised over
50 PhD students, all of whom he has always supervised himself
and most of whom have gone on to careers in industry, normallyin the area of multiphase ﬂow. Geoff has also managed many major, very successful initiatives. One major initiative is the TransientMultiphase Flow project (1996 – present), with signiﬁcant collaborations from co-workers at other universities, namely Bristol,Cambridge, Cranﬁeld, and Nottingham, and support from the oiland gas industry as well as the Research Councils, UK. Anotherinitiative is the very successful multi-university project on foulingin crude oil pre-heat trains in reﬁneries, the effects of which cost
the US alone more than $2B pa. Other projects include those on
distillation, multiphase mass ﬂow metering (of vital interest forﬁscal/tax purposes), and a variety of novel small nuclear reactors(where large is by no means necessarily beautiful).
Geoff’s success is down to his incredible drive, burning ambition, infectious work ethic, unbounded enthusiasm, incrediblememory, (incredible ﬁling system!), and natural leadership skills.
Geoff was an outstanding public speaker, knowledgeable, deeply
insightful, and incredibly convincing. He has left an indelible markwherever he went, with the kind of lasting impact on academia,industry, engineering practice, and, most importantly, people, that
only Geoff could create.
Professor Giota Angeli of UCL, a former PhD student of Geoff’s, recalls fondly how almost every “have you tried this?” from
Geoff resulted in a far-from-straightforward, yet incredibly insightful, experiment. Professor Jader Barbosa of the Federal University of
Santa Catarina, Brazil, who completed his thesis under Geoff’s supervision said “Geoff Hewitt was my role model, my guiding star. I
will never forget when, as a ﬁrst-year PhD student, I ﬁrst showed
him my calculations on droplet concentration imbalance and how
it explained the anomalous behaviour of the heat transfer coeﬃcient in annular ﬂow of mixtures. His enthusiastic reply (‘‘There isnothing like it, Jader!’’) synthesised the passion for science and thepleasure of discovery that I strive to pass on to my students every2O. K. Matar, P. Angeli and M. Kawaji / International Journal of Multiphase Flow 122 (2020) 103164

day.” Professor Prashant Valluri of the University of Edinburgh, andanother former student of Geoff’s, reminds us that “[Geoff] wasindeed larger-than-life and always open to crazy modelling ideas(like mine) to solve immensely challenging multiphase ﬂow problems… Though oﬃcially retired and Emeritus since 1999 (I joined
his group in 20 0 0), he used to say this when asked about hisretirement “I need to channel my so-called success to my team andmy students. I will only leave my oﬃce with my feet up.””
Geoff’s long-time collaborator, Professor Chris Lawrence, formerly of Imperial College London and presently at Schlumberger,
said “I had the privilege to work closely with Geoff Hewitt for
many years, and beneﬁtted hugely from his enthusiasm, generosity,and good humour. ‘The Geoff’ was uniquely talented in many ways,
with creative insight, a prodigious memory, and an insatiable appetite for research; he fully deserves the deﬁnite article awarded
to him by one of our students.”
Professor Neima Brauner of Tel Aviv University, a friend and colleague of Geoff’s said “We have lost a dear friend, whose scholarly work and personality enriched our lives for several decades.
For us, Geoff has been a model of a top scientist, a great educator, and a gentleman. We have always enjoyed meeting him,and exchanging views on science, culture, and political issues withhim. His charm and warm personality illuminated our interactions.
Geoff was a mentor, friend, brilliant scholar, and world-renowned
expert in multiphase ﬂows and transport phenomena, amongst
others. His impact on us, and on the younger scientists at TAU, will
be long lasting.”
Professor Masahiro Kawaji of the City College of New York, acollaborator and co-author of Geoff’s remarks that “Prof. Geoff Hewitt was undoubtedly one of the most respected experts on gasliquid two-phase ﬂow, having published extensively on many twophase ﬂow topics, focusing on fundamental physical mechanisms.
Two monographs, Annular Two-Phase Flow and Measurement ofTwo Phase Flow Parameters are well-known and highly usefulfor students, researchers and practicing engineers. Through theseand other publications including the well-known Heat Exchanger
Design Handbook, Professor Hewitt has made lasting contributions
to the ﬁeld of two-phase ﬂow and heat transfer.”
For all his work, Geoff has been recognised by his election to
the Fellowship of the Royal Academy of Engineering: he was afounding Fellow and later served as a member of its Council andof its Leverhulme Fellowships Committee. He has been elected toFellowship of the Royal Society, and the US National Academy ofEngineering. He has also been elected as a Fellow of the Institution of Chemical Engineers (IChemE) and was its President in 198990. Geoff has also won numerous prestigious international medals
and awards: Donald Q. Kern Award (American Institute of ChemicalEngineers), Max Jakob Memorial Award (American Society of Mechanical Engineers/American Institute of Chemical Engineers), theLuikov Medal, the Nusselt-Reynolds Prize, and the Senior Multiphase Flow Award at the International Conference on Multiphase
Flows in 2007. He was also awarded a Global Energy InternationalPrize in 2007. Geoff’s most recent award was in 2017: the Sharma
Medal from the IChemE.
For me personally, Geoff was a great friend, and a terriﬁc sourceof advice, humour, kindness, and support. It has been an honour
and a privilege for me to have known him, and to have worked
with him. As the late Barry Azzopardi used to say, Geoff was like agreat battleship, sailing magniﬁcently through the waters, and entraining us all in his bow waves. This is such an accurate description of Geoff the man, the scientist, and the visionary: always inrelentless pursuit of knowledge, but doing it with style, charisma,
and a smile none of us will ever forget.
Omar K. Matar
Panagiota Angeli
Masahiro Kawaji