Abstract
It is known that in classical fluids turbulence typically occurs at high Reynolds numbers. But can turbulence occur at low Reynolds numbers? Here we investigate the transition to turbulence in the classic Taylor-Couette system in which the rotating fluids are manufactured ferrofluids with magnetized nanoparticles embedded in liquid carriers. We find that, in the presence of a magnetic field transverse to the symmetry axis of the system, turbulence can occur at Reynolds numbers that are at least one order of magnitude smaller than those in conventional fluids. This is established by extensive computational ferrohydrodynamics through a detailed investigation of transitions in the flow structure, and characterization of behaviors of physical quantities such as the energy, the wave number, and the angular momentum through the bifurcations. A finding is that, as the magnetic field is increased, onset of turbulence can be determined accurately and reliably. Our results imply that experimental investigation of turbulence may be feasible by using ferrofluids. Our study of transition to and evolution of turbulence in the Taylor-Couette ferrofluidic flow system provides insights into the challenging problem of turbulence control.
Highlights
We investigate the Taylor-Couette flow[13] in finite systems where a rotating ferrofluid[14] is confined by axial end walls, i.e., non-rotating lids, in the presence of an external magnetic field
We find that turbulence can occur for Reynolds numbers at least one order of magnitude smaller than those required for turbulence to arise in conventional fluids
The pressure can be normalized by ρν2/d2, and the magnetic field H and the magnetization M by ρ/μ0 ν/d where μ0 is the magnetic permeability of free space
Summary
The classic Taylor-Couette flow of non-magnetic fluid has been a computational 15,16 and experimental[17,18,19] paradigm to investigate a variety of nonlinear and complex dynamical phenomena, including transition to turbulence at high Reynolds numbers[20]. The magnetic field can be used effectively as a control or bifurcation parameter of the system, whose change can lead to characteristically distinct types of hydrodynamical behaviors[22,23,24,25]. In this regard, transition to turbulence in magnetohydrodynamical (MHD) flows with current-driven instabilities of helical fields has been investigated[31]. Revisiting and exploring the field of turbulence in ferrofluids can be rewarding, which has become feasible due to progress in computational fluid dynamics
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
