Research contributions
Larson is an expert in the theory and simulations of rheology, fluid mechanics, and transport phenomena. His research contributions are in self-assembling soft matter, especially polymers, colloids, surfactant-containing fluids, liquid crystalline polymers, biological macromolecules such as DNA, proteins, and polyelectrolytes. Larson (along with Susan Muller at UC Berkeley and Eric Shaqfeh at Stanford) is known for the discovery of fluid mechanical instabilities of polymeric fluids in curved streamlines due to polymer stretching. [4] These type of streamlines, commonly found in Taylor-Couette flows, are of great importance to the polymer processing industry. Analogous instabilities have been known for over a century for ordinary fluids such as air and water, and these instabilities drive common phenomena such as weather patterns, as well as vortices and other phenomena in common industrial flows of liquids. He has developed molecular constitutive equations for entangled polymers, as well as many predictive theories for nonlinear rheology of branched polymers, polymers unraveling in shear and extensional flows, polymer drag reduction, shear-induced alignment transitions in block copolymers, slip and cavitation in polymer solutions and melts, and arrested tumbling of liquid crystalline polymers. [5] These methods have been used worldwide by researchers to understand and predict the flow properties of polymeric fluids.
Larson is the sole author of two textbooks, “Constitutive Equations for Polymer Melts and Solutions”, and “The Structure and Rheology of Complex Fluids”. He has also co-authored with John Dealy and Daniel Read on the book, “Structure and Rheology of Molten Polymers”.
According to Google Scholar, Larson's publications have received over 42,500 citations and his h-index is 87. [6]
Rheology is the study of the flow of matter, primarily in a fluid state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids.
The Deborah number (De) is a dimensionless number, often used in rheology to characterize the fluidity of materials under specific flow conditions. It quantifies the observation that given enough time even a solid-like material might flow, or a fluid-like material can act solid when it is deformed rapidly enough. Materials that have low relaxation times flow easily and as such show relatively rapid stress decay.
In materials science, a Bingham plastic is a viscoplastic material that behaves as a rigid body at low stresses but flows as a viscous fluid at high stress. It is named after Eugene C. Bingham who proposed its mathematical form.
In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed.
Denis James Evans, is an Australian scientist who is an Emeritus Professor at the Australian National University and Honorary Professor at The University of Queensland. He is widely recognised for his contributions to nonequilibrium thermodynamics and nonequilibrium statistical mechanics and the simulation of nonequilibrium fluids.
In rheology, shear thinning is the non-Newtonian behavior of fluids whose viscosity decreases under shear strain. It is sometimes considered synonymous for pseudo-plastic behaviour, and is usually defined as excluding time-dependent effects, such as thixotropy.
Manfred Hermann Wagner is the author of Wagner model and the molecular stress function theory for polymer rheology. He is a Professor for Polymer engineering and Polymer physics at the Technical University of Berlin.
The magnetorotational instability (MRI) is a fluid instability that causes an accretion disk orbiting a massive central object to become turbulent. It arises when the angular velocity of a conducting fluid in a magnetic field decreases as the distance from the rotation center increases. It is also known as the Velikhov–Chandrasekhar instability or Balbus–Hawley instability in the literature, not to be confused with the electrothermal Velikhov instability. The MRI is of particular relevance in astrophysics where it is an important part of the dynamics in accretion disks.
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per square metre, or pascal-seconds.
Leslie Gary Leal is the Warren & Katharine Schlinger Professor of Chemical Engineering at the University of California, Santa Barbara. He is known for his research work in the dynamics of complex fluids.
Michael Elmhirst Cates is a British physicist. He is the 19th Lucasian Professor of Mathematics at the University of Cambridge and has held this position since 1 July 2015. He was previously Professor of Natural Philosophy at the University of Edinburgh, and has held a Royal Society Research Professorship since 2007.
Masao Doi is a Professor Emeritus at Nagoya University and The University of Tokyo. He is a Fellow of the Toyota Physical and Chemical Research Institute. In 1978 and 1979 he wrote a series of papers with Sir Sam Edwards expanding on the concept of reptation introduced by Pierre-Gilles de Gennes in 1971. In 1996 he authored the textbook Introduction to Polymer Physics.
John Francis Brady is an American chemical engineer and the Chevron Professor of Chemical Engineering and Mechanical Engineering at the California Institute of Technology. He is a fluid mechanician and creator of the Stokesian dynamics method for simulating suspensions of spheres and ellipsoids in low Reynolds number flows. He is an elected fellow of the American Physical Society, a fellow of the Society of Rheology, as well as a member of the National Academy of Sciences, the National Academy of Engineering, and the American Academy of Arts and Sciences.
Viswanathan Kumaran is an Indian chemical engineer, rheologist and a professor at the Department of Chemical Engineering of the Indian Institute of Science. He is known for his studies on stability of flow past flexible surfaces and is an elected fellow of the Indian Academy of Sciences, Indian National Science Academy and the Indian National Academy of Engineering. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards for his contributions to Engineering Sciences in 2000. A recipient of the TWAS Prize in 2014 and the Infosys Prize 2016 in the Engineering and Computer Science category, Kumaran was listed in the Asian Scientist 100, a list of top 100 scientists from Asia, by the Asian Scientist magazine.
Christopher Ward Macosko (1944) is an American chemical engineer and professor emeritus in the department of chemical engineering and materials science at the University of Minnesota. He is internationally known for his work in polymer science and engineering, especially in the areas of rheology and polymer processing. Macosko is an author of more than 500 academic papers, dozens of patents, and two books including the text: "Rheology: Principles, Measurements and Applications". He served as director of the Industrial Partnership for Research in Interfacial and Materials Engineering (IPRIME), a university-industry consortium at the University of Minnesota, from 1999 to 2018. Macosko and his wife Kathleen have been married since 1967 and are long-time residents of Minneapolis. They have four children and 12 grandchildren.
Squeeze flow is a type of flow in which a material is pressed out or deformed between two parallel plates or objects. First explored in 1874 by Josef Stefan, squeeze flow describes the outward movement of a droplet of material, its area of contact with the plate surfaces, and the effects of internal and external factors such as temperature, viscoelasticity, and heterogeneity of the material. Several squeeze flow models exist to describe Newtonian and non-Newtonian fluids undergoing squeeze flow under various geometries and conditions. Numerous applications across scientific and engineering disciplines including rheometry, welding engineering, and materials science provide examples of squeeze flow in practical use.
Amalie L. Frischknecht is an American theoretical polymer physicist at Sandia National Laboratories in Albuquerque, New Mexico. She was elected a fellow of the American Physical Society (APS) in 2012 for "her outstanding contributions to the theory of ionomers and nanocomposites including the development and application of density functional theory to polymers". Her research focuses on understanding the structure, phase behavior, and self-assembly of polymer systems, such as complex fluids polymer nanocomposites, lipid bilayer assemblies, and ionomers.
Julia A. Kornfield is a Professor of Chemical Engineering at the California Institute of Technology. A world expert in polymer science, Kornfield's research encompasses the development of mega-supramolecular systems for fuel additives and intraocular lenses, as well as the influence of flow on polymer chains.
Surita Bhatia is an American chemist who is professor and vice provost of faculty affairs at Stony Brook University. Her work considers the structure of soft materials, including polymeric hydrogels and colloidal glasses. She was elected Fellow of the American Institute of Chemical Engineers, the American Institute for Medical and Biological Engineering and the Society of Rheology in 2020.
Lynn Walker is a professor of chemical engineering at Carnegie Mellon University. Her research considers the rheology of complex fluids and how nanostructure impacts the behavior of complex systems. She is a Fellow of the American Institute of Chemical Engineers, the Society of Rheology, and the American Physical Society.
