Ph.D., Fluid Mechanics
B.Sc., Mechanical Engineering
As the ASME Division of Fluids Engineering celebrates its 90th Anniversary, I make a broad-brush sweep of progress in the field of fluid mechanics during this period. Selected theoretical, numerical, and experimental advances are described. The inventions of laser and computer have profound effects on humanity, but their influence on fluid mechanics is particularly elucidated in this review.
The Taylor-Couette system keeps making subject to countless studies. It is used in catalytic reactors, electrochemistry, photochemistry, biochemistry and polymerization, as well as in mass transfer operations (extraction, tangential filtration, crystallization and dialysis). This work deals with a numerical study dedicated to a Taylor-Couette flow considering the influence of a pulsatile dynamic superimposed to the rotative inner cylinder. Simulations are implemented on the FLUENT commercial package where a three-dimensional and incompressible flow is considered. It is shown that the suggested controlling technique fundamentally alters the physical flow behavior resulting in substantial turbulence enhancement to which transition is instilled at a Taylor number of Ta = 17 instead of Ta = 41.33 corresponding to the non-controlled case.
Taylor--Couette flows have been extensively investigated due to their many industrial applications, such as catalytic reactors, electrochemistry, photochemistry, biochemistry, and polymerization. Mass transfer applications include extraction, tangential filtration, crystallization, and dialysis. A 3D study is carried out to simulate a Taylor--Couette flow with a rotating and pulsating inner cylinder. We utilize FLUENT to simulate the incompressible flow with a free surface. The study reveals that flow structuring is initiated with the development of an Ekman vortex at low Taylor number, Ta =0.01. For all encountered flow regimes, the Taylor vortices are systematically inhibited by the pulsatile motion of the inner cylinder. A spectral analysis shows that this pulsatile motion causes a rapid decay of the free surface oscillations, from a periodic wavy movement to a chaotic one, then to a fully turbulent motion. This degenerative free surface behavior is interpreted as the underlying mechanism responsible for the inhibition of the Taylor vortices.