Subhasish Dey (

Bengali Bengali or Bengalee, or Bengalese may refer to: *something of, from, or related to Bengal, a large region in South Asia * Bengalis, an ethnic and linguistic group of the region * Bengali language, the language they speak ** Bengali alphabet, the w ...

: শুভাশীষ দে; born 1958) is a hydraulician and educator. He is known for his research on the hydrodynamics and acclaimed for his contributions in developing theories and solution methodologies of various problems on

hydrodynamics In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids—liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) and ...

turbulence In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...

boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condi ...

sediment transport Sediment transport is the movement of solid particles (sediment), typically due to a combination of gravity acting on the sediment, and/or the movement of the fluid in which the sediment is entrained. Sediment transport occurs in natural system ...

and

open channel flow In fluid mechanics and hydraulics, open-channel flow is a type of liquid flow within a conduit with a free surface, known as a channel. The other type of flow within a conduit is pipe flow. These two types of flow are similar in many ways but di ...

. He is currently a distinguished professor of

Indian Institute of Technology Jodhpur Indian Institute of Technology Jodhpur (IIT Jodhpur or IITJ) is a public technical university located in Jodhpur in the state of Rajasthan in India. It is one of the eight new Indian Institutes of Technology (IITs) established by the Ministry ...

(2023–). Before, he worked as a professor of the department of civil engineering,

Indian Institute of Technology Kharagpur Indian Institute of Technology Kharagpur (IIT Kharagpur) is a public institute of technology established by the Government of India in Kharagpur, West Bengal, India. Established in 1951, the institute is the first of the IITs to be established ...

(1998–2023), where he served as the head of the department during 2013–15 and held the position of Brahmaputra Chair Professor during 2009–14 and 2015. He also held the adjunct professor position in the Physics and Applied Mathematics Unit at

Indian Statistical Institute Indian Statistical Institute (ISI) is a higher education and research institute which is recognized as an Institute of National Importance by the 1959 act of the Indian parliament. It grew out of the Statistical Laboratory set up by Prasanta C ...

Kolkata during 2014–19. Besides he has been named a distinguished visiting professor at the Tsinghua University in Beijing, China. Dey is an ''associate editor'' of ''

Journal of Geophysical Research The ''Journal of Geophysical Research'' is a peer-reviewed scientific journal. It is the flagship journal of the American Geophysical Union. It contains original research on the physical, chemical, and biological processes that contribute to the un ...

'' – ''Earth Surface'', '' Journal of Hydraulic Engineering'', ''Journal of Hydraulic Research'', ''Sedimentology'', ''Acta Geophysica'', ''Journal of Hydro-Environment Research'', ''International Journal of Sediment Research'' and ''Journal of Numerical Mathematics and Stochastics''. He is also an editorial board member of several journals including the ''

Proceedings of the Royal Society ''Proceedings of the Royal Society'' is the main research journal of the Royal Society. The journal began in 1831 and was split into two series in 1905: * Series A: for papers in physical sciences and mathematics. * Series B: for papers in life s ...

'' of London A: Mathematical, Physical and Engineering Sciences.

Brief biography

Dey was born to Bimalendu Dey (father) and Kana Dey (mother) in

Jalpaiguri Jalpaiguri is a city in the Indian state of West Bengal. It is the headquarters of the Jalpaiguri district as well as of the Jalpaiguri division of West Bengal, covering the jurisdiction of the five districts of North Bengal. The city is loca ...

town,

West Bengal West Bengal (, Bengali: ''Poshchim Bongo'', , abbr. WB) is a state in the eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabitants within an area of . West Bengal is the fourt ...

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

in 1958. In 1987, he married Swastika Dey (née Talukdar); and they have a son, Sibasish, and a daughter, Sagarika.

Career

Dey received B.E. degree in civil engineering from the

University of North Bengal University of North Bengal (abbreviated as NBU) is a public state collegiate major research university in North Bengal region of West Bengal, which is located in Raja Rammohanpur, Siliguri, Darjeeling district, in the Indian state of West Be ...

in 1981, MTech degree in water resources engineering and PhD degree in

hydraulic engineering Hydraulic engineering as a sub-discipline of civil engineering is concerned with the flow and conveyance of fluids, principally water and sewage. One feature of these systems is the extensive use of gravity as the motive force to cause the mov ...

from the

in 1984 and 1992, respectively. He started his professional career as a faculty of the National Institute of Technology Durgapur, where he taught

fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics of fluids ( liquids, gases, and plasmas) and the forces on them. It has applications in a wide range of disciplines, including mechanical, aerospace, civil, chemical and bio ...

and

hydraulics Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...

from 1984 to 1998. Then, he joined as a faculty of the

in 1998 and worked until June, 2023. Since July, 2023, he serves

as a distinguished professor.

Honors

Dey has become a ''fellow'' of the ''

Indian National Science Academy The Indian National Science Academy (INSA) is a national academy in New Delhi for Indian scientists in all branches of science and technology. In August 2019, Dr. Chandrima Shaha was appointed as the president of Indian National Science Academ ...

'' (''FNA''), ''

Indian Academy of Sciences The Indian Academy of Sciences, Bangalore was founded by Indian Physicist and Nobel Laureate C. V. Raman, and was registered as a society on 24 April 1934. Inaugurated on 31 July 1934, it began with 65 founding fellows. The first general meet ...

'' (''FASc''), ''

National Academy of Sciences, India The National Academy of Sciences, India, established in 1930, is the oldest science academy in India. It is located in Prayagraj, Uttar Pradesh. Prof. Meghnad Saha was the founder president. Fellows *Suddhasatwa Basu * Sudha Bhattacharya * Ch ...

'' (''FNASc'') and ''

Indian National Academy of Engineering The Indian National Academy of Engineering (INAE), founded in 1987, comprises India's engineers, engineer-scientists and technologists covering the entire spectrum of engineering disciplines. The Academy is registered under the Societies Reg ...

'' (''FNAE''). He received the ''JC Bose Fellowship'' award in 2018. He is the vice president of the council of ''World Association for Sedimentation and Erosion Research'' (''WASER'') (2019–2022). He served as a ''Council Member'' of the ''World Association for Sedimentation and Erosion Research'' (''WASER'') (2011–2013) and the ''International Association for Hydro-Environment Engineering and Research'' (''IAHR'') (2015–2019). He is also a ''Member'' of the ''IAHR Fluvial Hydraulics Committee''. Dey is ranked among the 150 most cited researchers in civil engineering i
Shanghai’s Global Ranking of Academics
Dey was conferred with the ''Hans Albert Einstein Award'' for “his fundamental contribution to the fluvial sediment transport, turbulence mechanism, local scour, and alluvial river dynamics from the perspectives of research, education and practice” from the ASCE in 2022.

Contributions

He has developed various theories of hydrodynamics. He discovered the origin of the scaling laws of

and the onset of a straight river to

meander A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank ( cut bank) and deposits sediments on an inner, convex bank ...

. In

, he developed universal

probability density function In probability theory, a probability density function (PDF), or density of a continuous random variable, is a function whose value at any given sample (or point) in the sample space (the set of possible values taken by the random variable) can ...

for turbulent velocity fluctuations,

Reynolds stress In fluid dynamics, the Reynolds stress is the component of the total stress tensor in a fluid obtained from the averaging operation over the Navier–Stokes equations to account for turbulent fluctuations in fluid momentum. Definition The veloci ...

and conditional Reynolds shear stresses in wall-shear flows. In

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

, he has contributed fundamental theories of sediment thresholds (also known as initiation of motion), discovered existence of negative hydrodynamic lift and non-universality of ''

von Kármán constant In fluid dynamics, the von Kármán constant (or Kármán's constant), named for Theodore von Kármán, is a dimensionless constant involved in the logarithmic law describing the distribution of the longitudinal velocity in the wall-normal direction ...

''. He has made pioneering contributions to the mechanism of

scour Scour may refer to: Hydrodynamic processes * Hydrodynamic scour, the removal of sediment such as sand and silt from around an object * Bridge scour, erosion of soil around at the base of a bridge pier or abutments via the flow of air, ice, or ...

at hydraulic structures. Besides, he has developed theories of secondary boundary layer in curved pipes, wall jets, seeping bed flows and turbulent bursting etc.

Books

References

* E. Padhi, N. Penna, S. Dey and R. Gaudio (2018). "Spatially-averaged dissipation rate in flows over water-worked and screeded gravel beds". ''Physics of Fluids'', American Institute of Physics (AIP), Vol. 30, No. 12, pp. 125106. * E. Padhi, N. Penna, S. Dey and R. Gaudio (2018). "Hydrodynamics of water-worked and screeded gravel beds: A comparative study". ''Physics of Fluids'', American Institute of Physics (AIP), Vol. 30, No. 8, pp. 085105. * H. Fang, X. Han, G. He and S. Dey (2018). "Influence of permeable beds on hydraulically macro-rough flow". ''Journal of Fluid Mechanics'', Cambridge University Press, UK, Vol. 847, No. July, 552–590. * S. Dey and S. Z. Ali (2018). "Review Article: Advances in modeling of bed particle entrainment sheared by turbulent flow". ''Physics of Fluids'', American Institute of Physics, Vol. 30, No. 6, pp. 061301. * S. Z. Ali and S. Dey (2018). "Impact of phenomenological theory of turbulence on pragmatic approach to fluvial hydraulics". ''Physics of Fluids'', American Institute of Physics, Vol. 30, No. 4, pp. 045105. * S. Z. Ali and S. Dey (2017). "Hydrodynamic instability of a meandering channel". ''Physics of Fluids'', American Institute of Physics, Vol. 29, No. 12, pp. 125107. * S. Dey and S. Z. Ali (2017). "Origin of the onset of meandering a straight river". ''Proceedings of the Royal Society A'', London, UK, Vol. 473, No. August, pp. 20170376. * S. Dey, G. Ravi Kishore, O. Castro-Orgaz and S. Z. Ali (2017). "Hydrodynamics of submerged turbulent plane offset jets". ''Physics of Fluids'', American Institute of Physics, Vol. 29, No. 6, pp. 065112. * S. Dey and S. Z. Ali (2017). "Stochastic mechanics of loose boundary particle transport in turbulent flow". ''Physics of Fluids'', American Institute of Physics, Vol. 29, No. 5, pp. 055103. * S. Dey and S. Z. Ali (2017). "Mechanics of sediment transport: Particle scale of entrainment to continuum scale of bedload flux". ''Journal of Engineering Mechanics'', American Society of Civil Engineers (ASCE), Vol. 143, No. 11, pp. 04017127. * S. Z. Ali and S. Dey (2017). "Origin of the scaling laws of sediment transport". ''Proceedings of the Royal Society A'', London, UK, Vol. 473, Issue 2197, pp. 20160785. * S. Z. Ali and S. Dey (2016). "Mechanics of advection of suspended particles in turbulent flow". ''Proceedings of the Royal Society A'', London, UK, Vol. 472, Issue, 2195, pp. 20160749. * S. Z. Ali and S. Dey (2016). "Hydrodynamics of sediment threshold". ''Physics of Fluids'', American Institute of Physics, Vol. 28, No. 7, pp. 075103. * S. Dey and R. Das (2012). "Gravel-bed hydrodynamics: A double-averaging approach". ''Journal of Hydraulic Engineering'', American Society of Civil Engineers (ASCE), Vol. 138, No. 8, 707–725. * S. Dey, S. Sarkar and F. Ballio (2011). "Double-averaging turbulence characteristics in seeping rough-bed streams". ''Journal of Geophysical Research, Earth Surface'', American Geophysical Union, Vol. 116, F03020, doi:10.1029/2010JF001832 * S. Dey, T. K. Nath and S. K. Bose (2010). "Submerged wall-jets subjected to injection and suction from the wall". ''Journal of Fluid Mechanics'', Cambridge University Press, UK, Vol. 653, 57–97. * R. Gaudio, R. Miglio and S. Dey (2010). "Nonuniversality of von Kármán’s κ in fluvial streams". ''Journal of Hydraulic Research'', International Association for Hydraulic Research (IAHR), Vol. 48, No. 5, 658–663. * S. K. Bose and S. Dey (2010). "Universal probability distributions of turbulence in open channel flows". ''Journal of Hydraulic Research'', International Association for Hydraulic Research (IAHR), Vol. 48, No. 3, 388–394. * S. K. Bose and S. Dey (2009). "Reynolds averaged theory of turbulent shear flow over undulating beds and formation of sand waves". ''Physical Review E'', The American Physical Society, Vol. 80, 036304. * S. K. Bose and S. Dey (2007). "Theory of free surface flow over rough seeping beds". ''Proceedings of the Royal Society A'', London, UK, Vol. 463, No. February, 369–383. * S. Dey and A. Sarkar (2006). "Response of velocity and turbulence in submerged wall jets to abrupt changes from smooth to rough beds and its application to scour downstream of an apron". ''Journal of Fluid Mechanics'', Cambridge University Press, UK, Vol. 556, 387–419. * S. Dey (2002). "Secondary boundary layer and wall shear for fully developed flow in curved pipes". ''Proceedings of the Royal Society A'', London, UK, Vol. 458, No. February, 283–294. * S. Dey (1999). "Sediment threshold". ''Applied Mathematical Modelling'', Elsevier, Vol. 23, No. 5, 399–417. * S. Dey, S. K. Bose and G. L. N. Sastry (1995). "Clear water scour at circular piers: a model". ''Journal of Hydraulic Engineering'', American Society of Civil Engineers (ASCE), Vol. 121, No. 12, 869–876. {{DEFAULTSORT:Dey, Subhasish Scientists from West Bengal Living people 1958 births Bengali Hindus Bengali scientists IIT Kharagpur alumni 20th-century Bengalis 21st-century Bengalis University of North Bengal alumni People from Jalpaiguri Hydraulic engineers Fluid dynamicists Indian fluid dynamicists 20th-century Indian educational theorists 20th-century Indian engineers Fellows of the Indian National Science Academy Fellows of the Indian Academy of Sciences Fellows of The National Academy of Sciences, India Fellows of the Indian National Academy of Engineering Academic staff of IIT Kharagpur Academic staff of the Indian Statistical Institute Academic staff of the National Institute of Technology, Durgapur

Brief biography

Career

Honors

Contributions

Books

References

Further reading