scholarly journals Size-dependent particle migration and trapping in three-dimensional microbubble streaming flows

2020 ◽  
Vol 5 (11) ◽  
Author(s):  
Andreas Volk ◽  
Massimiliano Rossi ◽  
Bhargav Rallabandi ◽  
Christian J. Kähler ◽  
Sascha Hilgenfeldt ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Particle Migration ◽  
Size Dependent ◽  
Streaming Flows

scholarly journals Additive Manufacturing and size-dependent mechanical properties of three-dimensional microarchitected, high-temperature ceramic metamaterials

2018 ◽  
Vol 33 (3) ◽  
pp. 360-371 ◽  
Author(s):  
Huachen Cui ◽  
Ryan Hensleigh ◽  
Hongshun Chen ◽  
Xiaoyu Zheng
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Three Dimensional ◽  
Size Dependent ◽  
Image Position

Abstract

scholarly journals A 3D particle Monte Carlo approach to studying nucleation

2017 ◽  
Author(s):  
Christoph Köhn ◽  
Martin Bødker Enghoff ◽  
Henrik Svensmark
Keyword(s):  
Monte Carlo ◽  
Sulphuric Acid ◽  
Nucleation Rate ◽  
Particle Density ◽  
Monte Carlo Model ◽  
Three Dimensional ◽  
Initial Particle ◽  
Time Step ◽  
Size Dependent ◽  
Discrete Nature

Abstract. The nucleation of sulphuric acid molecules plays a key role in the formation of aerosols. We here present a three dimensional particle Monte Carlo model to study the growth of sulphuric acid clusters as well as its dependence on the ambient temperature and the initial particle density.We initiate a swarm of sulphuric acid molecules with a size of 0.15 nm with densities between 107 and 108 cm−3 at temperatures of 200 and 300 K. After every time step, we update the position and velocity of particles as a function of size-dependent diffusion coefficients. If two particles encounter, we merge them and add their volumes and masses. Inversely, we check after every time step whether a polymer evaporates liberating a molecule.We present the spatial distribution as well as the size distribution calculated from individual clusters. We also calculate the nucleation rate of clusters with a radius of 0.85 nm as a function of time, initial particle density and temperature. For 200 K, the nucleation rate increases as a function of time; for 300 K we observe an interplay between clustering and evaporation and thus the oscillation of the nucleation rate around the mean nucleation rate. The nucleation rates obtained from the presented model agree well with experimentally obtained values which serves as a benchmark of our code. In contrast to previous nucleation models, we here present for the first time a code capable of tracing individual particles and thus of capturing the physics related to the discrete nature of particles.

scholarly journals Streaming patterns in Faraday waves

2017 ◽  
Vol 819 ◽  
pp. 285-310 ◽  
Author(s):  
Nicolas Périnet ◽  
Pablo Gutiérrez ◽  
Héctor Urra ◽  
Nicolás Mujica ◽  
Leonardo Gordillo
Keyword(s):  
Three Dimensional ◽  
Navier Stokes ◽  
Faraday Waves ◽  
Three Dimensional Model ◽  
Inviscid Fluids ◽  
Streaming Velocity ◽  
The Rich ◽  
Set Up ◽  
Viscous Boundary ◽  
Streaming Flows

Wave patterns in the Faraday instability have been studied for decades. Besides the rich wave dynamics observed at the interface, Faraday waves hide elusive flow patterns in the bulk – streaming patterns – which have not been studied experimentally. The streaming patterns are responsible for a net circulation in the flow, which is reminiscent of the circulation in convection cells. In this article, we analyse these streaming flows by conducting experiments in a Faraday-wave set-up using particle image velocimetry. To visualise the flows, we perform stroboscopic measurements to both generate trajectory maps and probe the streaming velocity field. We identify three types of patterns and experimentally show that identical Faraday waves can mask streaming patterns that are qualitatively very different. Next, we consider a three-dimensional model for streaming flows in quasi-inviscid fluids, whose key is the complex coupling occurring at all of the viscous boundary layers. This coupling yields modified boundary conditions in a three-dimensional Navier–Stokes formulation of the streaming flow. Numerical simulations based on this framework show reasonably good agreement, both qualitative and quantitative, with the velocity fields of our experiments. The model highlights the relevance of three-dimensional effects in the streaming patterns. Our simulations also reveal that the variety of streaming patterns is deeply linked to the boundary condition at the top interface, which may be strongly affected by the presence of contaminants.

scholarly journals Modeling the effects of size on patch dynamics of an inert tracer

2009 ◽  
Vol 6 (2) ◽  
pp. 1735-1756
Author(s):  
P. Xiu ◽  
F. Chai
Keyword(s):  
Dilution Rate ◽  
Ocean Circulation ◽  
Three Dimensional ◽  
Circulation Model ◽  
Patch Dynamics ◽  
Initial Size ◽  
Phytoplankton Productivity ◽  
Size Dependent ◽  
Enrichment Experiments

Abstract. Mesoscale iron enrichment experiments have revealed that additional iron affects the phytoplankton productivity and carbon cycle. However, the role of initial size of fertilized patch in determining the patch evolution is poorly quantified due to the limited time of research vessels at sea. Using a three-dimensional ocean circulation model, we simulated different sizes of inert tracer patches that were only regulated by physical circulation and diffusion. Model results showed that during the first few days since release of inert tracer, the calculated dilution rate was found to be a linear function with time, which was sensitive to the initial patch size with steeper slope for smaller size patch. After the initial phase of rapid decay, the relationship between dilution rate and time became an exponential function, which was also size dependent. Therefore, larger initial size patches can usually last longer and ultimately affect biogeochemical processes much stronger than smaller patches.

scholarly journals A three-dimensional surface elastic model for vibration analysis of functionally graded arbitrary straight-sided quadrilateral nanoplates under thermal environment

2020 ◽  
Vol 37 ◽  
pp. 72-99
Author(s):  
A Shahabodini ◽  
R Ansari ◽  
H Rouhi
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Thermal Environment ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Mapping Technique ◽  
Elastic Model ◽  
Size Dependent ◽  
Present Solution ◽  
Effect Of Surface

Abstract In this paper, a three-dimensional (3D) size-dependent formulation is developed for the free vibrations of functionally graded quadrilateral nanoplates subjected to thermal environment. The plate model is constructed within the frameworks of the Gurtin–Murdoch surface and the 3D elasticity theories. In this way, the effect of surface free energy and all the components of stress and strain tensors are considered without any initial assumption on them as there is no need to assume the variation of transverse normal stress inside the bulk material in advance. The variational differential quadrature approach and the mapping technique are applied to derive a discretized weak form of the governing equations. The present solution method bypasses the transformation and discretization of the higher order derivatives appearing in the equations of the strong form. The effects of surface stress, thermal environment, material gradient index and geometrical properties on the size-dependent vibrational behavior of quadrilateral nanoplates are investigated. It is observed that the thermal load intensifies the effect of surface free energy on the natural frequency of the nanoplates. The present model is exact in the extent of the continuum models and can be employed for structures with any thickness–span ratios.

A Droplet Size Dependent Multiphase Mixture Model and Three-dimensional Simulation of PEM Fuel Cells

2019 ◽  
Vol 19 (26) ◽  
pp. 51-64
Author(s):  
Guangli He ◽  
Yohtaro Yamazaki ◽  
Abuliti Abudula
Keyword(s):  
Fuel Cells ◽  
Mixture Model ◽  
Droplet Size ◽  
Three Dimensional ◽  
Pem Fuel Cells ◽  
Size Dependent ◽  
Multiphase Mixture ◽  
Dimensional Simulation

scholarly journals Particle migration and sorting in microbubble streaming flows

2016 ◽  
Vol 10 (1) ◽  
pp. 014124 ◽  
Author(s):  
Raqeeb Thameem ◽  
Bhargav Rallabandi ◽  
Sascha Hilgenfeldt
Keyword(s):  
Particle Migration ◽  
Streaming Flows

scholarly journals THE SURFACE- AND SIZE-DEPENDENT ELASTIC MODULI OF NANOSTRUCTURES

2007 ◽  
Vol 14 (04) ◽  
pp. 667-670 ◽  
Author(s):  
JIAN-GANG GUO ◽  
YA-PU ZHAO
Keyword(s):  
Theoretical Model ◽  
Surface Energy ◽  
Continuum Model ◽  
Elastic Moduli ◽  
Three Dimensional ◽  
Surface Effects ◽  
Surface Relaxation ◽  
Size Dependent ◽  
Analytical Expressions

A theoretical model is presented to investigate the size-dependent elastic moduli of nanostructures with the effects of the surface relaxation surface energy taken into consideration. At nanoscale, due to the large ratios of the surface-to-volume, the surface effects, which include surface relaxation surface energy, etc., can play important roles. Thus, the elastic moduli of nanostructures become surface- and size-dependent. In the research, the three-dimensional continuum model of the nanofilm with the surface effects is investigated. The analytical expressions of five nonzero elastic moduli of the nanofilm are derived, and then the dependence of the elastic moduli is discussed on the surface effects and the characteristic dimensions of nanofilms.

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