In
fluid dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion ...
, the Toms effect is a reduction of the drag of a
turbulent
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
flow through a pipeline when
polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...
solutions are added.
In 1948, B. A. Toms discovered by experiments that the addition of a small amount of polymer into a
Newtonian solvent (
parts per million
In science and engineering, the parts-per notation is a set of pseudo-units to describe the small values of miscellaneous dimensionless quantity, dimensionless quantities, e.g. mole fraction or mass fraction (chemistry), mass fraction.
Since t ...
by weight), which results in a
non-Newtonian fluid solution, can reduce the skin frictional drag on a stationary surface by up to 80% when turbulence is present.
This technology has been successfully implemented to reduce pumping cost for oil pipelines, to increase the flow rate in fire fighting equipment and to help irrigation and drainage.
[Khalil, M. F., Kassab, S. Z., Elmiligui, A. A. & Naoum, F. A. 2002 Applications of drag-reducing polymers in sprinkler irrigation systems: Sprinkler head performance. Journal of Irrigation and Drainage Engineering] It also has potential applications in the design of ship and submarine hulls to achieve an increased speed and reduced energy cost.
See also
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Drag reducing agent
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FENE model
In polymer physics, the finite extensible nonlinear elastic (FENE) model, also called the FENE dumbbell model, represents the dynamics of a long-chained polymer. It simplifies the chain of monomers by connecting a sequence of beads with nonlinea ...
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Non-Newtonian fluid
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Direct numerical simulation
A direct numerical simulation (DNS)https://eprints.soton.ac.uk/66182/1/A_primer_on_DNS.pdf "A Primer on Direct Numerical Simulation of Turbulence –
Methods, Procedures and Guidelines", Coleman and Sandberg, 2010 is a simulation in computational ...
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References
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External links
Alyeska Pipe LineEFFECTS OF FRICTION AND POLYMERS ON 2D TURBULENCE{{Non-Newtonian fluids
Polymers