Numerical Modeling Of Formation Research Articles

Numerical Model for Formation and Evolution of the Bleb

The morphology of a bleb and its changes are critical to the amoeboid migration of a cell. By releasing bonds between the membrane and the cortex of a cell, the formation of a bleb can be observed experimentally, but the mechanism that affects the size and shape of a bleb during amoeboid migration requires further study. In this study, by adapting the governing equations and discrete equations of the two-dimensional fluid–solid coupling model recommended by Strychalski and Guy [2013 “A computational model of bleb formation,” Mathematical Medicine and Biology 30(2), 115–130], we overcome the defect that the bleb by traditional means is always too small compared with experimental results, and simulate the behaviors of cell blebs successfully. The effects of various parameters such as the number of broken bonds, the viscosity coefficient of the cortex, and the cell’s membrane modulus on the size and the shape of the bleb are investigated. Numerical results show that the model effectively simulates the formation and evolution of a bleb, thus, the contributions of several factors to bleb shape and size are successfully derived.

Numerical Modeling of Formation and Rise of Gas and Dust Cloud from Large Scale Commercial Blasting

The emission of dust particles into the atmosphere during rock mass breaking by blasting in ore mining open-pits is one of the factors that determine the ground-level air pollution in the vicinity of pits. The data on dust concentration in the cloud, which is extremely difficult to obtain experimentally for large-scale explosions, is required to calculate the dust dispersion in the wind stream. We have elaborated a Eulerian model to simulate the initial stage of dust cloud formation and rising, and a Navier–Stokes model to simulate thermal rising and mixing with the ambient air. The first model is used to describe the dust cloud formation after a 500 t TNT (Trinitrotoluene equivalent) explosion. The second model based on the Large Eddy Simulation (LES) method is used to predict the height of cloud rising, its mass, and the evolution of dust particles size distribution for explosions of 1–1000 t TNT. It was found that the value of the turbulent eddy viscosity coefficient (Smagorinsky coefficient) depends on both the charge mass and the spatial resolution (grid cell size). The values of the Smagorinsky coefficient were found for charges with a mass of 1–1000 t using a specific grid.

Mathematical modelling of moist convection and transport of gaseous pollutants and aerosols in clouds

AbstractA joint three-dimensional numerical model of formation of convective clouds in the atmosphere is constructed with a detailed description of microphysical processes. A transport model of multicomponent gaseous admixtures and aerosols is also a constructed subject to gas-phase and liquid-phase chemical reactions. Basic physical mechanisms of formation of liquid droplet clouds of medium size and the transport of gases with different reactivity and solubility are considered. The calculations performed with the use of the data on emission of NO

Numerical Modeling of Formation of High-Speed Water Slugs

The objective of this work is to investigate acceleration of a water slug by the powder explosion. The process occurs in a device termed the water cannon, which entails a barrel with an attached nozzle. The explosion products expel the slug from the barrel at an extremely high speed. Due to the acceleration in the nozzle the speed of the slug significantly exceeds that of a bullet driven by the similar explosion. The computational procedure was used to evaluate the pressure, velocity and density fields in the course of slug acceleration in the x-t space. The procedure is based on the finite difference method and the method of characteristics. The initial water velocity and pressure are assumed to be zero. The pressure at water-explosion product interface is determined by the conditions of the powder combustion while the pressure at the water-atmosphere interface is equal to zero. The results of the computations enable us to explain the peculiarities of the operation of the water cannon and to optimize device design.