Direct numerical simulation of magnetic particles suspended in a Newtonian fluid exhibiting finite inertia under SAOS

Abstract

A direct numerical simulation approach is utilized to understand the oscillatory shear rheology of a confined suspension of magnetic chains formed by paramagnetic circular cylinders under the influence of an external magnetic field. The common assumption of gap-spanning chains made in the literature is relaxed in this work, so that a fully suspended (periodic) array of magnetic chains is formed. In this sense, the effective rheological parameters are only influenced through a layer of fluid adjacent to the walls. All tests are conducted at very low but finite particle Reynolds numbers, and typical inertial effects are discussed. The main aim of the present study is to investigate the apparent viscoelasticity of the system as a function of the external magnetic field and frequency of the input strain. This work concentrates on cases with large blockage ratio in order to have pronounced viscoelastic behaviours.

The Role of Volume Fraction and Additives on the Rheology of Suspensions of Micron Sized Iron Particles

“…We have found one paper (Lacis and Gosko, 2009) using an expression similar to Equation (1), with some tables derived from FEM simulations for two particles and another based on FEM simulations between several particles in a single chain (Kang et al, 2012). A simulation method, called smooth particle dynamics (Hashemi et al, 2016(Hashemi et al, , 2018, can also be used to solve the magnetostatics equation between several particles, but is restricted to a few particles with a rather small (<10) susceptibility. As discussed in the next section, the use of a magnetic force derived from FEM, calculated with a very fine mesh for two particles, is quite realistic and certainly much more efficient in terms of computing time.…”

A continuum model for magnetic particle flows in microfluidics applicable from dilute to packed suspensions

“…Another approach is direct numerical simulations (DNS), where particle motion and interstitial flow are directly resolved. 29 This powerful method is notably able to capture the elastic deformation and collision of soft nonspherical particles such as red blood cells. 30,31 However, this method requires high computational efforts, and simulations may take days for very simple problems, making the computational cost prohibitive for microfluidic systems with ten to hundred thousands of particles.…”

Simulation Study on the Motion of Magnetic Particles in Silicone Rubber‐Based Magnetorheological Elastomers

“…However, there are few studies on the chain formation of magnetic particles in MRE under magnetic field, the existing research generally analyzes the formation of chain by magnetic dipole theory [15,16] or study on the final arrangement of magnetic particle chains by changing the influence of different external conditions [17], and there is less quantitative analysis of magnetic particle motion during MRE curing. In addition, the magnetic particle motion under the applied magnetic field was difficult to observe because of the limitation of particle size, so the motion of the particle was often described by numerical simulation [18][19][20][21].…”