ORCID Profile
0000-0001-8894-0395
Current Organisation
Basque Center for Applied Mathematics
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Publisher: Springer Science and Business Media LLC
Date: 23-09-2016
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 02-2021
Publisher: AIP
Date: 2005
DOI: 10.1063/1.1941522
Publisher: American Physical Society (APS)
Date: 05-06-2008
Publisher: American Physical Society (APS)
Date: 23-10-2003
Publisher: Society for Industrial & Applied Mathematics (SIAM)
Date: 2006
DOI: 10.1137/060651367
Publisher: American Physical Society (APS)
Date: 22-05-2009
Publisher: AIP Publishing
Date: 12-2018
DOI: 10.1063/1.5054067
Publisher: AIP Publishing
Date: 09-2021
DOI: 10.1063/5.0059707
Abstract: The espresso extraction process involves a complex transport inside a geometry-changing porous medium. Large solid grains forming the majority of the porous medium can migrate, swell, and consolidate, and they can also morphologically change during flow, i.e., being mechanically eroded by hydrodynamic forces. These processes can, in turn, have a significant back-effect on the flow and the related coffee extraction profiles. In this article, we devise a bottom–up erosion model in the framework of smoothed dissipative particle dynamics to consider flow-induced morphological changes of the coffee grains. We assume that the coffee grains are not completely wetted and remain brittle. We found that heterogeneity in both the filtration direction and the transverse direction can be induced. The former is controlled by the angle of internal friction while the latter is controlled by both the cohesion parameter and the angle of internal friction. Not restricted to the modeling of espresso extraction, our model can also be applied to other eroding porous media. Our results suggest that, under ideal porous flow conditions, we can control the heterogeneity (in both the pressure drop direction and the transverse direction) of an eroding medium by tuning the yield characteristics of the eroding material.
Publisher: AIP Publishing
Date: 2021
DOI: 10.1063/5.0035936
Abstract: In this work, a methodology to perform rheological studies on smoothed dissipative particle dynamics under arbitrary flow configurations is introduced. To evaluate the accuracy and flexibility of the proposed methodology, viscometric studies for Newtonian fluids under pure shear, pure extension, and arbitrary flows in bulk or near walls are introduced. The applicability of this methodology to obtain viscoelastic properties of non-Newtonian fluids, such as polymer solutions, is also presented. The new computational approach offers relevant advantages in a variety of applications ranging from multiscale simulations to the rheological characterization of complex flows.
Publisher: AIP Publishing
Date: 10-03-2023
DOI: 10.1063/5.0136833
Abstract: Functionalized nanoparticles (NPs) are complex objects present in a variety of systems ranging from synthetic grafted nanoparticles to viruses. The morphology and number of the decorating groups can vary widely between systems. Thus, the modeling of functionalized NPs typically considers simplified spherical objects as a first-order approximation. At the nanoscale label, complex hydrodynamic interactions are expected to emerge as the morphological features of the particles change, and they can be further lified when the NPs are confined or near walls. Direct estimation of these variations can be inferred via diffusion coefficients of the NPs. However, the evaluation of the coefficients requires an improved representation of the NPs morphology to reproduce important features hidden by simplified spherical models. Here, we characterize the passive transport of free and confined functionalized nanoparticles using the Rigid Multi-Blob (RMB) method. The main advantage of RMB is its versatility to approximate the mobility of complex structures at the nanoscale with significant accuracy and reduced computational cost. In particular, we investigate the effect of functional groups’ distribution, size, and morphology over nanoparticle translational and rotational diffusion. We identify that the presence of functional groups significantly affects the rotational diffusion of the nanoparticles moreover, the morphology of the groups and number induce characteristic mobility reduction compared to non-functionalized nanoparticles. Confined NPs also evidenced important alterations in their diffusivity, with distinctive signatures in the off-diagonal contributions of the rotational diffusion. These results can be exploited in various applications, including biomedical, polymer nanocomposite fabrication, drug delivery, and imaging.
Publisher: American Physical Society (APS)
Date: 22-03-2012
Publisher: Wiley
Date: 05-09-2014
DOI: 10.1002/CNM.2591
Abstract: A novel multiscale Lagrangian particle solver based on SPH is developed with the intended application of leukocyte transport in large arteries. In such arteries, the transport of leukocytes and red blood cells can be ided into two distinct regions: the bulk flow and the near-wall region. In the bulk flow, the transport can be modeled on a continuum basis as the transport of passive scalar concentrations. Whereas in the near-wall region, specific particle tracking of the leukocytes is required and lubrication forces need to be separately taken into account. Because of large separation of spatio-temporal scales involved in the problem, simulations of red blood cells and leukocytes are handled separately. In order to take the exchange of leukocytes between the bulk fluid and the near-wall region into account, solutions are communicated through coupling of conserved quantities at the interface between these regions. Because the particle tracking is limited to those leukocytes lying in the near-wall region only, our approach brings considerable speedup to the simulation of leukocyte circulation in a test geometry of a backward-facing step, which encompasses many flow features observed in vivo.
Publisher: Elsevier BV
Date: 2012
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 08-01-2022
DOI: 10.1007/S40324-021-00280-Z
Abstract: A stochastic Lagrangian model for simulating the dynamics and rheology of a Brownian multi-particle system interacting with a simple liquid medium is presented. The discrete particle model is formulated within the GENERIC framework for Non-Equilibrium Thermodynamics and therefore it satisfies discretely the First/Second Laws of Thermodynamics and the Fluctuation Dissipation Theorem (FDT). Long-range fluctuating hydrodynamics interactions between suspended particles are described by an explicit solvent model. To this purpose, the Smoothed Dissipative Particle Dynamics method is adopted, which is a GENERIC-compliant Lagrangian meshless discretization of the fluctuating Navier–Stokes equations. In dense multi-particle systems, the average inter-particle distance is typically small compared to the particle size and short-range hydrodynamics interactions play a major role. In order to bypass an explicit—computationally costly—solution for these forces, a lubrication correction is introduced based on semi-analytical expressions for spheres under Stokes flow conditions. We generalize here the lubrication formalism to Brownian conditions, where an additional thermal-lubrication contribution needs to be taken into account in a way that discretely satisfies FDT. The coupled lubrication dynamics is integrated in time using a generalized semi-implicit splitting scheme for stochastic differential equations. The model is finally validated for a single particle diffusion as well as for a Brownian multi-particle system under homogeneous shear flow. Results for the diffusional properties as well as the rheological behavior of the whole suspension are presented and discussed.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0SM01173H
Abstract: A suspension of magnetic chains under the effect of an external rotating field and applied shear flow is simulated. The suspension viscosity can be controlled (increased or lowered) by tuning the magnetic frequency with the natural shear frequency.
Publisher: Elsevier BV
Date: 11-2023
Publisher: Elsevier BV
Date: 11-2014
Publisher: AIP Publishing
Date: 2012
DOI: 10.1063/1.3676244
Abstract: We apply smoothed dissipative particle dynamics (SDPD) [Español and Revenga, Phys. Rev. E 67, 026705 (2003)] to model solid particles in suspension. SDPD is a thermodynamically consistent version of smoothed particle hydrodynamics (SPH) and can be interpreted as a multiscale particle framework linking the macroscopic SPH to the mesoscopic dissipative particle dynamics (DPD) method. Rigid structures of arbitrary shape embedded in the fluid are modeled by frozen particles on which artificial velocities are assigned in order to satisfy exactly the no-slip boundary condition on the solid-liquid interface. The dynamics of the rigid structures is decoupled from the solvent by solving extra equations for the rigid body translational/angular velocities derived from the total drag/torque exerted by the surrounding liquid. The correct scaling of the SDPD thermal fluctuations with the fluid-particle size allows us to describe the behavior of the particle suspension on spatial scales ranging continuously from the diffusion-dominated regime typical of sub-micron-sized objects towards the non-Brownian regime characterizing macro-continuum flow conditions. Extensive tests of the method are performed for the case of two/three dimensional bulk particle-system both in Brownian/non-Brownian environment showing numerical convergence and excellent agreement with analytical theories. Finally, to illustrate the ability of the model to couple with external boundary geometries, the effect of confinement on the diffusional properties of a single sphere within a micro-channel is considered, and the dependence of the diffusion coefficient on the wall-separation distance is evaluated and compared with available analytical results.
Publisher: Elsevier BV
Date: 07-2002
Publisher: Society of Rheology
Date: 21-11-2022
DOI: 10.1122/8.0000527
Abstract: Constitutive models for the dynamics of polymer solutions traditionally rely on closure relations for the extra stress or related microstructural variables (e.g., conformation tensor) linking them to flow history. In this work, we study the eigendynamics of the conformation tensor within the GENERIC framework in mesoscopic computer simulations of polymer solutions to separate the effects of nonaffine motion from other sources of non-Newtonian behavior. We observe that nonaffine motion or slip increases with both the polymer concentration and the polymer chain length. Our analysis allows to uniquely calibrate a mixed derivative of the Gordon–Schowalter type in macroscopic models based on a micro-macromapping of the dynamics of the polymeric system. The presented approach paves the way for better polymer constitutive modeling in multiscale simulations of polymer solutions, where different sources of non-Newtonian behavior are modelled independently.
Publisher: Cambridge University Press (CUP)
Date: 10-08-2023
DOI: 10.1017/JFM.2023.540
Abstract: We introduce a fully Lagrangian heterogeneous multiscale method (LHMM) to model complex fluids with microscopic features that can extend over large spatio/temporal scales, such as polymeric solutions and multiphasic systems. The proposed approach discretizes the fluctuating Navier–Stokes equations in a particle-based setting using smoothed dissipative particle dynamics (SDPD). This multiscale method uses microscopic information derived on-the-fly to provide the stress tensor of the momentum balance in a macroscale problem, therefore bypassing the need for approximate constitutive relations for the stress. We exploit the intrinsic multiscale features of SDPD to account for thermal fluctuations as the characteristic size of the discretizing particles decreases. We validate the LHMM using different flow configurations (reverse Poiseuille flow, flow passing a cylinder array and flow around a square cavity) and fluid (Newtonian and non-Newtonian). We show the framework's flexibility to model complex fluids at the microscale using multiphase and polymeric systems. We also show that stresses are adequately captured and passed from micro to macro scales, leading to richer fluid response at the continuum. In general, the proposed methodology provides a natural link between variations at a macroscale, whereas accounting for memory effects of microscales.
Publisher: Springer International Publishing
Date: 11-12-2020
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 2015
Publisher: AIP Publishing
Date: 13-01-2009
DOI: 10.1063/1.3058437
Abstract: Smoothed dissipative particle dynamics (SDPD) is a novel coarse grained method for the numerical simulation of complex fluids. It has considerable advantages over more traditional particle-based methods. In this paper we analyze the self-diffusion coefficient D of a SDPD solvent by using the strategy proposed by Groot and Warren [J. Chem. Phys. 107, 4423 (1997)]. An analytical expression for D in terms of the model parameters is developed and verified by numerical simulations.
Publisher: Elsevier BV
Date: 07-2023
Publisher: Springer Science and Business Media LLC
Date: 31-05-2013
Publisher: Springer Science and Business Media LLC
Date: 30-12-2017
Publisher: American Physical Society (APS)
Date: 15-12-2120
Publisher: Springer Science and Business Media LLC
Date: 06-03-2012
Publisher: Society of Rheology
Date: 16-02-2023
DOI: 10.1122/8.0000514
Abstract: The rheology of concentrated suspensions of particles is complex and typically exhibits a shear-thickening behavior in the case of repulsive interactions. Despite the recent interest arisen, the causes of the shear-thickening remain unclear. Frictional contacts have been able to explain the discontinuous shear thickening in simulations. However, the interparticle friction coefficient is considered to be constant in most simulations and theoretical works reported to date despite the fact that tribological experiments demonstrate that the friction coefficient can not only be constant (boundary regime) but also decrease (mixed regime) or even increase (full-film lubrication regime), depending on the normal force and the relative velocity between the particles and the interstitial liquid between them. Interestingly, the transition between the boundary regime and the full-lubrication regime is governed by the particle average roughness. Particle-level simulations of suspensions of hard spheres were carried out using short-range lubrication and roughness-dependent frictional forces describing the full Stribeck curve. Suspensions with different particle’s roughness were simulated to show that the particle roughness is a key factor in the shear-thickening behavior for sufficiently rough particles, the suspension exhibits a remarkable shear-thickening, while for sufficiently smooth particles, the discontinuous shear-thickening disappears.
Publisher: Springer Science and Business Media LLC
Date: 25-04-2015
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 09-2005
Publisher: Elsevier BV
Date: 12-2005
Publisher: AIP Publishing
Date: 20-01-2018
DOI: 10.1063/1.3050100
Abstract: Dissipative particle dynamics (DPD) as a model of fluid particles suffers from the problem that it has no physical scale associated with the particles. Therefore, a DPD simulation requires an ambiguous fine-tuning of the model parameters with the physical parameters. A corrected version of DPD that does not suffer from this problem is smoothed dissipative particle dynamics (SDPD) [P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003)]. SDPD is, in fact, a version of the well-known smoothed particle hydrodynamics method, albeit with the proper inclusion of thermal fluctuations. Here, we show that SDPD produces the proper scaling of the fluctuations as the resolution of the simulation is varied. This is investigated in two problems: the Brownian motion of a spherical colloidal particle and a polymer molecule in suspension.
Publisher: Springer Netherlands
Date: 2009
Publisher: Wiley
Date: 28-12-2010
DOI: 10.1002/NME.3088
Publisher: American Physical Society (APS)
Date: 10-01-2007
Publisher: Cold Spring Harbor Laboratory
Date: 03-01-2022
DOI: 10.1101/2022.01.03.474721
Abstract: Many viruses, such as SARS-CoV-2 or Influenza, possess spike-decorated envelopes. Depending on the virus type, a large variability is present in spikes number, morphology and reactivity, which remains generally unexplained. Since viruses’ transmissibility depend on features beyond their genetic sequence, new tools are required to discern the effects of spikes functionality, interaction, and morphology. Here, we postulate the relevance of hydrodynamic interactions in the viral infectivity of enveloped viruses and propose micro-rheological characterization as a platform for viruses differentiation. To understand how the spikes affect virion mobility and infectivity, we investigate the diffusivity of spike-decorate structures using mesoscopic-hydrodynamic simulations. Furthermore, we explored the interplay between affinity and passive viral transport. Our results revealed that the diffusional mechanism of SARS-CoV-2 is strongly influenced by the size and distribution of its spikes. We propose and validate a universal mechanism to explain the link between optimal virion structure and maximal infectivity for many virus families.
Publisher: Elsevier BV
Date: 09-2004
Publisher: AIP Publishing
Date: 07-2016
DOI: 10.1063/1.4954815
Abstract: An analytical solution for the calculation of the normal lubrication force acting between two moving spheres embedded in a shear-thinning fluid represented by a bi-viscous model is provided. The resulting force between the suspended spheres exhibits a consistent transition between the Newtonian constant-viscosity limits and it reduces to the well-known standard Newtonian lubrication theory for viscosity-ratio approaching one. Effects of several physical parameters of the theory are analyzed under relevant physical conditions, i.e., for a prototypical case of two non-colloidal spheres immersed in a non-Newtonian fluid with rheology parameterized by a bi-viscosity model. Topological results for high/low-viscosity regions in the gap between spheres are also analyzed in detail showing a rich phenomenology. The presented model enables the extension of lubrication dynamics for suspensions interacting with non-Newtonian matrices and provides a clean theoretical framework for new numerical computations of flow of dense complex particulate systems.
Publisher: MDPI AG
Date: 06-02-2016
Publisher: American Physical Society (APS)
Date: 05-10-2010
Publisher: AIP Publishing
Date: 03-2017
DOI: 10.1063/1.4978630
Abstract: In this work, an analytical model for the behavior of superparamagnetic chains under the effect of a rotating magnetic field is presented. It is postulated that the relevant mechanisms for describing the shape and breakup of the chains into smaller fragments are the induced dipole-dipole magnetic force on the external beads, their translational and rotational drag forces, and the tangential lubrication between particles. Under this assumption, the characteristic S-shape of the chain can be qualitatively understood. Furthermore, based on a straight chain approximation, a novel analytical expression for the critical frequency for the chain breakup is obtained. In order to validate the model, the analytical expressions are compared with full three-dimensional smoothed particle hydrodynamics simulations of magnetic beads showing excellent agreement. Comparison with previous theoretical results and experimental data is also reported.
Publisher: American Physical Society (APS)
Date: 31-08-2016
Publisher: American Physical Society (APS)
Date: 05-03-3013
Publisher: AIP
Date: 2008
DOI: 10.1063/1.2964620
Publisher: Elsevier BV
Date: 07-2020
Publisher: Elsevier BV
Date: 10-2017
Publisher: AIP Publishing
Date: 10-2017
DOI: 10.1063/1.4997053
Abstract: In this work, an analytical solution for the pressure-driven flow of a discontinuous shear-thickening (DST) fluid in a planar channel is presented. In order to model the fluid rheology, a regularized inverse-biviscous model is adopted. This involves a region of finite thickness to model the sharp jump in viscosity, and it is consistent with momentum conservation. In the limit of vanishing thickness, the truly DST behavior is obtained. Analytical results are validated by numerical simulations under steady and start-up flow using the smoothed particle hydrodynamics method. Flow results are investigated and discussed for different values of the model parameters.
Publisher: American Physical Society (APS)
Date: 22-04-2013
Publisher: Cambridge University Press (CUP)
Date: 18-10-2019
DOI: 10.1017/JFM.2019.753
Abstract: We study the rheology of a non-colloidal suspension of rigid spherical particles interacting with a viscoelastic matrix. Three-dimensional numerical simulations under shear flow are performed using the smoothed particle hydrodynamics method and compared with experimental data available in the literature using different constant-viscosity elastic Boger fluids. The rheological properties of the Boger matrices are matched in simulation under viscometric flow conditions. Suspension rheology under dilute to semi-concentrated conditions (i.e. up to solid volume fraction $\\unicode[STIX]{x1D719}=0.3$ ) is explored. It is found that at small Deborah numbers $De$ (based on the macroscopic imposed shear rate), relative suspension viscosities $\\unicode[STIX]{x1D702}_{r}$ exhibit a plateau at every concentration investigated. By increasing $De$ , shear thickening is observed, which is related to the extensional thickening of the underlying viscoelastic matrix. Under dilute conditions ( $\\unicode[STIX]{x1D719}=0.05$ ), numerical results for $\\unicode[STIX]{x1D702}_{r}$ agree quantitatively with experimental data in both the $De$ and $\\unicode[STIX]{x1D719}$ dependences. Even under dilute conditions, simulations of full many-particle systems with no a priori specification of their spatial distribution need to be considered to recover precisely experimental values. By increasing the solid volume fraction towards $\\unicode[STIX]{x1D719}=0.3$ , despite the fact that the trend is well captured, the agreement remains qualitative with discrepancies arising in the absolute values of $\\unicode[STIX]{x1D702}_{r}$ obtained from simulations and experiments but also with large deviations existing among different experiments. With regard to the specific mechanism of elastic thickening, the microstructural analysis shows that elastic thickening correlates well with the average viscoelastic dissipation function $\\unicode[STIX]{x1D703}^{elast}$ , requiring a scaling as $\\langle \\unicode[STIX]{x1D703}^{elast}\\rangle \\sim De^{\\unicode[STIX]{x1D6FC}}$ with $\\unicode[STIX]{x1D6FC}\\geqslant 2$ to take place. Locally, despite the fact that regions of large polymer stretching (and viscoelastic dissipation) can occur everywhere in the domain, flow regions uniquely responsible for the elastic thickening are well correlated to areas with significant extensional component.
Publisher: AIP Publishing
Date: 09-11-2017
DOI: 10.1063/1.4993610
Abstract: In this work, we extend the three-dimensional Smoothed Particle Hydrodynamics (SPH) non-colloidal particulate model previously developed for Newtonian suspending media in Vázquez-Quesada and Ellero [“Rheology and microstructure of non-colloidal suspensions under shear studied with smoothed particle hydrodynamics,” J. Non-Newtonian Fluid Mech. 233, 37–47 (2016)] to viscoelastic matrices. For the solvent medium, the coarse-grained SPH viscoelastic formulation proposed in Vázquez-Quesada, Ellero, and Español [“Smoothed particle hydrodynamic model for viscoelastic fluids with thermal fluctuations,” Phys. Rev. E 79, 056707 (2009)] is adopted. The property of this particular set of equations is that they are entirely derived within the general equation for non-equilibrium reversible-irreversible coupling formalism and therefore enjoy automatically thermodynamic consistency. The viscoelastic model is derived through a physical specification of a conformation-tensor-dependent entropy function for the fluid particles. In the simple case of suspended Hookean dumbbells, this delivers a specific SPH discretization of the Oldroyd-B constitutive equation. We validate the suspended particle model by studying the dynamics of single and mutually interacting “noncolloidal” rigid spheres under shear flow and in the presence of confinement. Numerical results agree well with available numerical and experimental data. It is straightforward to extend the particulate model to Brownian conditions and to more complex viscoelastic solvents.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 2007
Publisher: American Physical Society (APS)
Date: 10-12-2010
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Marco Ellero.