scholarly journals Assessing the influence of metallicity on fragmentation of proto-galactic gas

2006 ◽  
Vol 2 (14) ◽  
pp. 268-268
Author(s):  
Anne-Katharina Jappsen ◽  
Simon C. O. Glover ◽  
Ralf S. Klessen ◽  
Mordecai-Mark Mac Low

AbstractIn cold dark matter cosmological models, the first stars to form are believed to do so within small protogalaxies. We study the influence of low levels of metal enrichment on the cooling and collapse of ionized gas in these protogalactic halos using three-dimensional, smoothed particle hydrodynamics simulations.

2009 ◽  
Vol 5 (S265) ◽  
pp. 65-66
Author(s):  
Anne-Katharina Jappsen ◽  
Simon C. O. Glover ◽  
Mordecai-Mark Mac Low ◽  
Ralf S. Klessen

AbstractThe formation of the first stars out of metal-free gas appears to result in stars at least an order of magnitude more massive than in the present-day case. We here consider what controls the transition from a primordial to a modern initial mass function. We study the influence of low levels of metal enrichment and different initial conditions on the cooling and collapse of initially ionized gas in small protogalactic halos using three-dimensional, smoothed particle hydrodynamics simulations. We argue that fragmentation at moderate density depends on the initial conditions for star formation more than on the metal abundances present.


2020 ◽  
Vol 17 (10) ◽  
pp. 2050009
Author(s):  
Sisi Tan ◽  
Mingze Xu

Numerical modeling of whole blood still faces great challenges although significant progress has been achieved in recent decades, because of the large differences of physical and geometric properties among blood components, including red blood cells (RBCs), platelets (PLTs) and white blood cells (WBCs). In this work, we develop a three-dimensional (3D) smoothed particle hydrodynamics (SPH) model to study the whole blood in shear flow. The immersed boundary method (IBM) is used to deal with the interaction between the fluid and cells, which provides a possibility to model the RBCs, PLTs and WBCs simultaneously. The deformation of a small capsule, comparable to a PLT in size, is first examined to show the feasibility of SPH model for the PLTs’ behaviors. The motion of a single RBC in shear flow is then studied, and three typical modes, tank-treading, swinging and tumbling motions, are reproduced, which further confirm the reliability of the SPH model. After that, a simulation of the whole blood in shear flow is carried out, in which the margination trend is observed for both PLTs and WBC. This shows the capability of SPH model with IBM for the simulation of whole blood.


2019 ◽  
Vol 95 ◽  
pp. 02011
Author(s):  
Anisa Wulandari ◽  
R.R Dwinanti Rika ◽  
Jessica Sjah ◽  
Herr Soeryantono

Scouring Phenomenon directly occurs on materials due to the motion of water flow and water borne sediments that researchers in the world continue to investigate. Scouring are then continuously developed in Computational Fluid Dynamics (CFD) to be able to estimate scouring effects by analyzing interaction between fluid and solid. Water and solid interaction can be researched by realizing three dimensional numerical modeling (3D) using Smoothed Particle Hydrodynamics Method which is modeling and visualizing fluid behavior with a Lagrangian approach in particle scale (micro scale), a more particle approach realistic than the grid approach. Using this method, the results of each particle can be reviewed either by their property values or visually so that the results are obtained more representatives. One of the factors affecting fluid-solid modeling is spacing ratio between solid particle and fluid particle. To obtain the correct physical results, it is required to consider the influence of spacing ratio and the value of Stiffness Coefficient (Ks) needed.


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