scholarly journals Modelling of Non-Spherical Particles in Dilute Non-Colloidal Suspensions Using SPH

2020 ◽  
Author(s):  
Nadine Kijanski ◽  
David Krach ◽  
Holger Steeb
Keyword(s):  
Numerical Simulations ◽  
Influence Factors ◽  
Colloidal Suspensions ◽  
Direct Numerical Simulations ◽  
Contact Forces ◽  
Solid Particles ◽  
Spherical Particles ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Dilute Suspensions

Suspensions and their applications can be found in many engineering, environmental or medical fields. Considering the special field of dilute suspensions, possible applications are cement paste or procedural processes in the production of medication or food. While the homogenized behavior of these applications is well understood, contributions in the field of pore-scale fully resolved numerical simulations with non-spherical particles are rare. Using Smoothed Particle Hydrodynamics as a simulation framework we therefore present a model for Direct Numerical Simulations of single-phase fluid containing non-spherically formed solid aggregates. Notable and discussed model specifications are the surface-coupled fluid-solid interaction forces as well as the contact forces between solid aggregates. Moreover we simulate and analyze the behavior of dilute non-colloidal suspensions of non-spherical solid particles in Newtonian fluids. The focus of this contribution is the numerical model for suspensions and its implementation in SPH. Therefore shown numerical examples present application examples for a first numerical analysis of influence factors in suspension flow. Results show that direct numerical simulations reproduce known phenomena like shear induced migration very well. Moreover the present investigation exemplifies the influence of concentration and form of particles on the flow processes in greater detail.

scholarly journals An SPH Approach for Non-Spherical Particles Immersed in Newtonian Fluids

2020 ◽  
Author(s):  
Nadine Kijanski ◽  
David Krach ◽  
Holger Steeb
Keyword(s):  
Numerical Simulations ◽  
Construction Materials ◽  
Contact Forces ◽  
Solid Particles ◽  
Spherical Particles ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Solid Bodies ◽  
Fluid Solid Interaction ◽  
Modelling Approach

Solid particles immersed in a fluid can be found in many engineering, environmental or medical fields. Applications are suspensions, sedimentation processes or procedural processes in the production of medication, food or construction materials. While homogenized behavior of these applications is well understood, contributions in the field of pore-scale fully resolved numerical simulations with non-spherical particles are rare. Using Smoothed Particle Hydrodynamics (SPH) as a simulation framework, we therefore present a modelling approach for Direct Numerical Simulations (DNS) of single-phase fluid containing non-spherically formed solid aggregates. Notable and discussed model specifications are the surface-coupled fluid-solid interaction forces as well as the contact forces between solid aggregates. The focus of this contribution is the numerical modelling approach and its implementation in SPH. Since SPH presents a fully resolved approach, the construction of arbitrary shaped particles is conveniently realizable. After validating our model for single non-spherical particles, we therefore investigate the motion of solid bodies in a Newtonian fluid and their interaction with the surrounding fluid by analyzing velocity fields of shear flow with respect to hydromechanical and contact forces. Results show a dependency of the motion and interaction of solid particles on their form and orientation. While spherical particles move to the centerline region, ellipsoidal particles move and rotate due to vortexes formation in the fluid flow in between.

scholarly journals An SPH Approach for Non-Spherical Particles Immersed in Newtonian Fluids

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2324
Author(s):  
Nadine Kijanski ◽  
David Krach ◽  
Holger Steeb
Keyword(s):  
Numerical Simulations ◽  
Vortex Formation ◽  
Construction Materials ◽  
Contact Forces ◽  
Solid Particles ◽  
Spherical Particles ◽  
Modeling Approach ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Solid Bodies

Solid particles immersed in a fluid can be found in many engineering, environmental or medical fields. Applications are suspensions, sedimentation processes or procedural processes in the production of medication, food or construction materials. While homogenized behavior of these applications is well understood, contributions in the field of pore-scale fully resolved numerical simulations with non-spherical particles are rare. Using Smoothed Particle Hydrodynamics (SPH) as a simulation framework, we therefore present a modeling approach for Direct Numerical Simulations (DNS) of single-phase fluid containing non-spherically formed solid aggregates. Notable and discussed model specifications are the surface-coupled fluid–solid interaction forces as well as the contact forces between solid aggregates. The focus of this contribution is the numerical modeling approach and its implementation in SPH. Since SPH presents a fully resolved approach, the construction of arbitrary shaped particles is conveniently realizable. After validating our model for single non-spherical particles, we therefore investigate the motion of solid bodies in a Newtonian fluid and their interaction with the surrounding fluid and with other solid bodies by analyzing velocity fields of shear flow with respect to hydromechanical and contact forces. Results show a dependency of the motion and interaction of solid particles on their form and orientation. While spherical particles move to the centerline region, ellipsoidal particles move and rotate due to vortex formation in the fluid flow in between.

Simulation of Impaction Between Liquid Droplet and Solid Particles Based on SPH Method

2014 ◽  
Author(s):  
Shuai Meng ◽  
Qian Wang ◽  
Rui Yang
Keyword(s):  
Surface Tension ◽  
Solid Particle ◽  
Liquid Droplet ◽  
Particle Interaction ◽  
Solid Particles ◽  
Seed Particle ◽  
Liquid Droplets ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Spray Granulation

The phenomenon of impaction between liquid droplets and solid particles is involved in many scientific problems and engineering applications, such as impaction between sprayed droplet and solid particles in limestone injection desulfurization system and the collision between a droplet of the liquid to be granulated and a seed particle in fluidized bed spray granulation process. There are a lot of factors affected this phenomenon: droplet and particle size, momentum of both liquid droplet and solid particles, materials, surface conditions of the solid particles and so on. However the experimental or numerical researches have been done mostly pay attention to Specific application or process, so the impaction phenomenon has not been through studied, for example how different factors affected the impaction process with its effect on different applications. This paper focuses on the basic issue of interaction between droplet and solid particles. Three main factors were considered: ratio of diameter between the droplet and solid particle, relative velocity and the surface tension (including the contact angle between droplet and solid particle). All the study is based on simulation using SPH (smoothed particle hydrodynamics) method, and the surface tension is simulated by particle-particle interaction.

scholarly journals Numerical simulations of surf zone wave dynamics using Smoothed Particle Hydrodynamics

2019 ◽  
Vol 144 ◽  
pp. 101481 ◽  
Author(s):  
R.J. Lowe ◽  
M.L. Buckley ◽  
C. Altomare ◽  
D.P. Rijnsdorp ◽  
Y. Yao ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Smoothed Particle Hydrodynamics ◽  
Surf Zone ◽  
Wave Dynamics ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Non-Spheric Colloidal Suspensions in Three-Dimensional Space

1997 ◽  
Vol 08 (04) ◽  
pp. 985-997 ◽  
Author(s):  
Dewei Qi
Keyword(s):  
Reynolds Number ◽  
Dimensional Space ◽  
Low Reynolds Number ◽  
Paper Industry ◽  
Three Dimensional ◽  
Colloidal Suspensions ◽  
Solid Particles ◽  
Spherical Particles ◽  
Dynamic Simulations ◽  
Low Reynolds

The translation and rotation of non-spherical particles, such as ellipsoidal, cylindric or disk-like pigment particles, in a Couette flow system similar to a blade coating system in the paper industry6 have been successfully simulated by using the lattice-Boltzmann method combined with Newtonian dynamic simulations. Hydrodynamic forces and torques are obtained by the use of boundary conditions which match the moving surface of solid particles. Then Euler equations have been integrated to include three-dimensional rotations of the suspensions by using four quaternion parameters as generalized coordinates. The three-dimensional rotations have been clearly observed. Consequently, the motion of the particles suspended in fluids of both low-Reynolds-number and finite-Reynolds-number, up to several hundreds, has been studied. It appears that the 3D translation and rotation of the non-spherical particles are more clearly observed in a high-Reynolds-number fluid than in a low-Reynolds-number fluid.

scholarly journals Direct numerical simulations of dense suspensions: wave instabilities in liquid-fluidized beds

2007 ◽  
Vol 587 ◽  
pp. 303-336 ◽  
Author(s):  
J. J. DERKSEN ◽  
S. SUNDARESAN
Keyword(s):  
Numerical Simulations ◽  
Bulk Viscosity ◽  
Fluid Model ◽  
Travelling Waves ◽  
System Size ◽  
Direct Numerical Simulations ◽  
Fluid Particle ◽  
Spherical Particles ◽  
Particle Phase ◽  
Viscosity Term

We present results of direct numerical simulations of travelling waves in dense assemblies of monodisperse spherical particles fluidized by a liquid. The cases we study have been derived from the experimental work of others. In these simulations, the flow of interstitial fluid is solved by the lattice-Boltzmann method (LBM) and the particles move under the influence of gravity, hydrodynamic forces stemming from the LBM, subgrid-scale lubrication forces and hard-sphere collisions. We first show that the propagating inhomogeneous structures seen in the simulations are in agreement with those observed experimentally. We then use the detailed information contained in the simulation results to assess aspects of two-fluid model closures, namely, fluid–particle drag, and the various contributions to the effective stresses. We show that the rates of compaction and dilation of the particle phase in the travelling waves are comparable to the rate at which the microstructure relaxes, and that there is a pronounced effect of the rate of compaction on the average collisional normal stress. Although this effect can be expressed as an effective bulk viscosity term, this approach would require the use of a path-dependent bulk viscosity. We also find that the effective fluid–particle drag coefficient can be described well with the often-used closure motivated by the experiments of Richardson & Zaki (Trans. Inst. Chem. Engng vol. 32, 1954, p. 35). In this respect, the effect of the system size for determining the drag requires specific care. The shear viscosity of the particle phase manifests small, but clearly noticeable dependence on the rate of compaction/dilation of the particle phase. Our observations point to the need for higher-order closures that recognize the slow evolution of the microstructure in these flows and account for the effects of non-equilibrium microstructure on the stresses.

scholarly journals Virtual motion of real particles

2010 ◽  
Vol 650 ◽  
pp. 1-4 ◽  
Author(s):  
G. TRYGGVASON
Keyword(s):  
Kinetic Energy ◽  
Numerical Simulations ◽  
Turbulent Kinetic Energy ◽  
Multiphase Flows ◽  
Isotropic Turbulence ◽  
Finite Size ◽  
Direct Numerical Simulations ◽  
Spherical Particles ◽  
Length Scale ◽  
Turbulent Eddies

Direct numerical simulations are rapidly becoming one of the most important techniques to examine the dynamics of multiphase flows. Lucci, Ferrante & Elghobashi (J. Fluid Mech., 2010, this issue, vol. 650, pp. 5–55) address several fundamental issues for spherical particles in isotropic turbulence. They show the importance of including the finite size of the particles and discuss how particles of a size comparable to the largest length scale at which viscosity substantially affects the turbulent eddies (i.e. the Taylor microscale) always increase the dissipation of turbulent kinetic energy.

scholarly journals A MULTI-NODE APPROACH TO SIMULATE THIN COASTAL STRUCTURES IN THE SPH CONTEXT

2017 ◽  
pp. 1
Author(s):  
Francesco Aristodemo ◽  
Domenico Davide Meringolo ◽  
Paolo Veltri
Keyword(s):  
Computational Cost ◽  
Variable Parameter ◽  
The Body ◽  
Solid Particles ◽  
Solid Boundary ◽  
Ghost Particle ◽  
Weakly Compressible ◽  
Boundary Treatment ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

We propose an improvement in modeling solid boundary conditions for 2D weakly-compressible Smoothed Particle Hydrodynamics (SPH) simulations for cases in which the thickness of the body is small compared to the desired particle size and the fluid surrounds the body from more than one side. Specifically, the fixed ghost particles technique developed by Marrone et al. (2011), based on interpolation nodes located within the fluid domain, is here extended to a multi-node approach. The fluid domain is thus divided into various sub-areas and an interpolation node for the considered solid particle is associated to every sub-area. Consequently, the solid particles present an array of values interpolated at different sub-areas for the same physical quantity. When a fluid particle located in a specific region interacts with a multi-node fixed ghost particle, the last assumes the field values interpolated in the reference area through the associated node. The present modeling allows to adopt a coarser spatial resolution to model the same physical problem, resulting in a reduction of the computational cost. The proposed solid boundary treatment is applied to horizontal decks and perforated wall-caisson breakwaters subjected to regular waves. In this context, an automatic hybrid diffusive formulation is introduced in order to prevent shock waves during water impacts and preserve the hydrostatic pressure. The formulation is obtained by defining a variable parameter detecting the occurrence of relevant density gradients induced by fluid impacts, resulting in an automatic switch between the two formulations.

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