Abstract
Experimental results reveal that the asymmetric flow of shear-thinning fluid through a cylindrical pipe, which was previously associated with the laminar-turbulent transition process, appears to have the characteristics of a nonhysteretic, supercritical instability of the laminar base state. Contrary to what was previously believed, classical transition is found to be responsible for returning symmetry to the flow. An absence of evidence of the instability in simulations (either linear or nonlinear) suggests that an element of physics is lacking in the commonly used rheological model for inelastic shear-thinning fluids. These unexpected discoveries raise new questions regarding the stability of these practically important fluids and how they can be successfully modeled.
Highlights
Pipe flow of non-Newtonian fluids is of great practical importance because many manmade fluids are non-Newtonian, for example, cosmetics and food products like shampoos or sauces, and the manufacturing processes for these fluids invariably involve pipe flow
Much progress has been made in recent years through the discovery of exact solutions to the Navier-Stokes equations at transitional Reynolds numbers (Re) [3,4,5,6,7,8] and how the footprints of these solutions persist into fully turbulent flows [9]
The most confusing aspect of the flow of non-Newtonian fluids is the asymmetric form the velocity profile takes at transitional Reynolds numbers (≈103 to 104) in a pipe of circular
Summary
Pipe flow of non-Newtonian fluids is of great practical importance because many manmade fluids are non-Newtonian, for example, cosmetics and food products like shampoos or sauces, and the manufacturing processes for these fluids invariably involve pipe flow. The most confusing aspect of the flow of non-Newtonian fluids is the asymmetric form the velocity profile takes at transitional Reynolds numbers (≈103 to 104) in a pipe of circular
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
