The turbidity current (TC), a ubiquitous fluid–particle coupled phenomenon in the natural environment and engineering, can transport over long distances on an inclined terrain due to suspension mechanism. A large-eddy simulation discrete element method model is employed simulate particle-laden gravity currents slope order investigate auto-suspension mechanism from Lagrangian perspective. particle Reynolds number our TC $0.01\sim 0.1$ angle $1/20 \sim 1/5$ . influences of initial...

The motion of microorganisms in complex fluids stands out as a prominent subject within fluid mechanics. In our study, we utilize the fictitious domain method to investigate locomotion squirmers along convex wall Giesekus viscoelastic fluids. This study examines influence elasticity and curvature on squirmer particles, analyzing their movement patterns detail. Near wall, three distinct behavioral characteristics emerge: scattering, orbiting forward, backward. findings reveal that, compared...

We experimentally investigate the finite-size spherical particle migration in micro-rectangular channels a Newtonian fluid (22 wt. % glycerol aqueous solution) and viscoelastic (8 polyvinylpyrrolidone at various size to hydraulic diameter ratios a/Dh channel aspect H/W. Experiments are performed rectangular low Reynolds numbers (Re) Weissenberg (Wi) ranging from 0.09 1.53. Particles almost mono-disperse neutrally buoyant polystyrene spheres with diameters of 20 μm, 30 50 μm. The 1, ½, 1/3....

The effects of the particle collision model in a direct-forcing fictitious domain method on fluid and statistics fully developed turbulent channel flow laden with finite-size neutrally buoyant particles are numerically investigated. collisions described by combination discrete element lubrication force correction model. We first validate our code via several benchmark tests, including normal particle–wall at different impact Stokes numbers oblique varied incidence angles. Subsequently,...

A parallel direct-forcing fictitious domain method is employed to perform interface-resolved numerical simulations of the interactions between neutrally buoyant finite-size spheroidal particles and turbulent channel flows. The effects aspect ratio on turbulence modulation rotation are investigated at friction Reynolds number 180, with particle equivalent diameter width being 0.1, volume fraction ranging from 0.79% 14.16%, 1/3 8. Our results show that flow decreases as prolate become more...

This experimental and theoretical study is devoted to the investigation of head-on collisions two immiscible Newtonian non-Newtonian droplets. The density droplets similar, viscosity 0.3% carboxymethyl cellulose droplet slightly larger than 10 cSt silicone oil. sizes relative velocity colliding close point impact are measured by means image processing. deformed states after their evolution with time studied visualization energy discussed numerical results. accuracy two-dimensional...

Binary droplet collisions are a key mechanism in powder coatings production, as well spray combustion, ink-jet printing, and other processes. The collision behavior of the droplets using Newtonian polymer liquids is studied numerically by coupled level-set volume fluid (CLSVOF) method adaptive mesh refinement (AMR). deformation process, internal flow fields, energy evolution discussed detail. For binary collisions, compared with liquid, maximum promoted. Due to increased viscous dissipation,...

The deformation and breakup of a polymer solution droplet plays key role in inkjet printing technology, tablet-coating process, other spray processes. In this study, the bag behavior is investigated numerically. simple coupled level set volume fluid (S-CLSVOF) method adaptive mesh refinement (AMR) technique are employed cases at different Weber numbers Ohnesorge numbers. nature handled using Herschel–Bulkley constitutive equations to describe shear-thinning behavior. Breakup processes,...

A turbulent channel flow of a binary mixture finite-size neutrally buoyant ellipsoidal particles is studied by using parallel direct-forcing fictitious domain method at friction Reynolds number 180 and the particle aspect ratios 1/3 (oblate particle) 4 (prolate particle), respectively. The total volume fraction fixed 14.16% 21.24% relative prolate oblate are varied. mean velocity profile normalized bulk shows strong difference between single phase particulate flow, while showing small...

Multigrain/polydispersity has a significant impact on turbidity current (TC). Despite the fact that several researches have looked into this effect, of fluid–particle interactions is not fully understood. Motivated by this, we employ Eulerian–Lagrangian computational fluid dynamics–discrete element method model to investigate dynamics bidisperse lock-exchange TC. Results show that, because coarse particles will settle faster and stop moving forward, two phases transport fine component can be...

In this article, an immiscible three-phase/three-component lattice Boltzmann flux solver (TPLBFS) based on diffusion interface method is proposed, which can achieve three-phase flow simulation with high density ratio (1:1000). This model quickly solved (1) the at grid using (LBM) solution format and (2) Navier–Stokes (NS) equation Cahn–Hilliard (CH) a unified format. Compared to LBM, TPLBFS be applied unstructured networks. Moreover, independently add or remove source items has secondary...

In industrial environments, droplet deformation and breakup in hot airflow are universal. The effect of temperature (293–473 K) on the silicone oil droplets continuous was studied. morphology, stage, regime map discussed detail by varying Weber number this paper. results show that regimes consistent with water (5 < We 30) considered However, has an obvious modes. nodes generated at toroidal rim is verified to be same as droplet, following “the combined Rayleigh–Taylor /aerodynamic...

The accurate sedimentation of metal droplets is great importance in droplet-based three-dimensional printing. Detailed investigations the process droplet collision a liquid–liquid system are still lacking, relative to studies on atmospheric environment. In this study, dynamics behavior experimentally investigated using high-speed imaging system. experimental results showed that with an increased impact velocity, successively appear after as coalescence, coalescence accompanied by rebound,...

Experimental research is done to determine the shear-thinning behavior of a bidisperse non-colloidal suspension under steady-state shear and strain-stiffening oscillatory shear. The second displayed when volume fraction particle between medium high. It exhibits with an increase in rate, viscosity drops by approximately three orders magnitude. At low rates, strong size dependence observed, while at high almost non-existent. To further understand thinning, sets tests (constant rate) are...

Uneven coatings with overspray often occur to the target plate when using a pneumatic atomizer. This issue is mainly due high-level pressure in center, which results from unreasonable design of structure and operating parameters In this paper, an optimal for these was established by response surface method (RSM) computational fluid dynamics (CFD) produce more uniform coatings. The velocity data measured hot-wire anemometry experimentally verified numerical model. Then, annular air hole...