scholarly journals Numerical Model for Formation and Evolution of the Bleb

2021 ◽  
Vol 13 (01) ◽  
pp. 2150009
Author(s):  
Jiju Feng ◽  
Liqun Tang ◽  
Zejia Liu ◽  
Shoubin Dong ◽  
Licheng Zhou ◽  
...  
Keyword(s):  
Viscosity Coefficient ◽  
Coupling Model ◽  
Two Dimensional ◽  
Governing Equations ◽  
Discrete Equations ◽  
A Cell ◽  
Bleb Formation ◽  
Formation And Evolution ◽  
Mathematical Medicine ◽  
Shape And Size

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.

scholarly journals Numerical Model for Formation and Evolution of the Bleb

2020 ◽  
Author(s):  
J. Feng ◽  
L. Tang ◽  
Z. Liu ◽  
S. Dong ◽  
L. Zhou ◽  
...  
Keyword(s):  
Cell Migration ◽  
Numerical Model ◽  
Cell Model ◽  
Viscosity Coefficient ◽  
Coupling Model ◽  
Impact Factors ◽  
Affecting Factors ◽  
A Cell ◽  
Formation And Evolution

ABSTRACTThe bleb morphology and its changes are an important mechanism of cell’s amoeboid migration. By releasing bonds between the membrane and the cortex of a cell, the formation of bleb can be observed experimentally, but the mechanism that affects the size and shape of this kind of bleb is waiting for further study. In this paper, a two-dimensional fluid-solid coupling model is established to describe a cell with membrane, cortex and cytoplasm in a solution, and a numerical solving method for the fluid-solid coupling model is developed to simulate the behaviors of cell bleb. The effects of 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 were investigated. Numerical results show that the model is effective to simulate the formation and evolution of cell’s bleb, and derive the contribution of several affecting factors to the bleb shape and size clearly.SIGNIFICANCETo understand the process of cell migration with bleb pseudopods in the amoeba cell migration, it is necessary to study the formation mechanism of cells protruding bleb. In this paper, we propose a reasonable and reliable cell numerical model. With this model we successfully simulate the bleb phenomenon consistent with the experimental phenomenon by changing the key impact factors. The method in this paper is applicable to the cell model of amoeba cell migration pattern, which helps to understand the important role of blebs in the process of cell migration.

scholarly journals Influence of a Standing Wave Flow-Field on the Dynamics of a Spray Diffusion Flame

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
J. Barry Greenberg ◽  
David Katoshevski
Keyword(s):  
Liquid Phase ◽  
Flow Field ◽  
Standing Wave ◽  
Diffusion Flame ◽  
Stokes Number ◽  
Flame Height ◽  
Wave Flow ◽  
Two Dimensional ◽  
Governing Equations ◽  
First Time

A theoretical investigation of the influence of a standing wave flow-field on the dynamics of a laminar two-dimensional spray diffusion flame is presented for the first time. The mathematical analysis permits mild slip between the droplets and their host surroundings. For the liquid phase, the use of a small Stokes number as the perturbation parameater enables a solution of the governing equations to be developed. Influence of the standing wave flow-field on droplet grouping is described by a specially constructed modification of the vaporization Damkohler number. Instantaneous flame front shapes are found via a solution for the usual Schwab–Zeldovitch parameter. Numerical results obtained from the analytical solution uncover the strong bearing that droplet grouping, induced by the standing wave flow-field, can have on flame height, shape, and type (over- or under-ventilated) and on the existence of multiple flame fronts.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

Review of Three Dimensional Dynamic Analyses of Circular Cylinders and Cylindrical Shells

1994 ◽  
Vol 47 (10) ◽  
pp. 501-516 ◽  
Author(s):  
Kostas P. Soldatos
Keyword(s):  
Cylindrical Shells ◽  
Three Dimensional ◽  
Circular Cylinders ◽  
Accurate Information ◽  
Two Dimensional ◽  
Governing Equations ◽  
Complicated Form ◽  
Dynamic Analyses ◽  
Cylindrical Panels ◽  
Elastic Cylinders

There is an increasing usefulness of exact three-dimensional analyses of elastic cylinders and cylindrical shells in composite materials applications. Such analyses are considered as benchmarks for the range of applicability of corresponding studies based on two-dimensional and/or finite element modeling. Moreover, they provide valuable, accurate information in cases that corresponding predictions based on that later kind of approximate modeling is not satisfactory. Due to the complicated form of the governing equations of elasticity, such three-dimensional analyses are comparatively rare in the literature. There is therefore a need for further developments in that area. A survey of the literature dealing with three-dimensional dynamic analyses of cylinders and open cylindrical panels will serve towards such developments. This paper presents such a survey within the framework of linear elasticity.

scholarly journals Two-dimensional numerical modeling of chemical transport–transformation in fluvial rivers: formulation of equations and physical interpretation

2009 ◽  
Vol 11 (2) ◽  
pp. 106-118 ◽  
Author(s):  
Sui Liang Huang
Keyword(s):  
Sediment Transport ◽  
Chemical Transport ◽  
Transformation Model ◽  
Diffusion Equations ◽  
Desorption Kinetics ◽  
Two Dimensional ◽  
Transformation Equation ◽  
Governing Equations ◽  
Convection Diffusion ◽  
Kinetics Of

Based on previous work on the transport–transformation model of heavy metal pollutants in fluvial rivers, this paper presents the formulation of a two-dimensional model to describe chemical transport–transformation in fluvial rivers by considering basic principles of environmental chemistry, hydraulics and mechanics of sediment transport and recent developments along with three very simplified test cases. The model consists of water flow governing equations, sediment transport governing equations, transport–transformation equation of chemicals and convection–diffusion equations of sorption–desorption kinetics of particulate chemical concentrations on suspended load, bed load and bed sediment. The chemical transport–transformation equation is basically a mass balance equation. It demonstrates how sediment transport affects transport–transformation of chemicals in fluvial rivers. The convection–diffusion equations of sorption–desorption kinetics of chemicals, being an extension of batch reactor experimental results, take both physical transport, i.e. convection and diffusion, and chemical reactions, i.e. sorption–desorption into account. The effects of sediment transport on chemical transport–transformation were clarified through three simple examples. Specifically, the transport–transformation of chemicals in a steady, uniform and equilibrium sediment-laden flow was calculated by applying this model, and results were shown to be rational. Both theoretical analysis and numerical simulation indicated that the transport–transformation of chemicals in sediment-laden flows with a clay-enriched riverbed possesses not only the generality of common tracer pollutants, but also characteristics of transport–transformation induced by sediment motion. Future work will be conducted to present the validation/application of the model with available data.

scholarly journals Comparison of West Balkan adult trout habitat predictions using a Pseudo-2D and a 2D hydrodynamic model

2016 ◽  
Vol 48 (6) ◽  
pp. 1697-1709 ◽  
Author(s):  
Christina Papadaki ◽  
Vasilis Bellos ◽  
Lazaros Ntoanidis ◽  
Elias Dimitriou
Keyword(s):  
Hydrodynamic Model ◽  
River Discharge ◽  
Environmental Flow ◽  
Two Dimensional ◽  
Habitat Models ◽  
One Dimensional ◽  
2D Flow ◽  
A Cell ◽  
The One ◽  
Water Depths

Abstract Hydraulic-habitat models combine the dynamic behavior of river discharge with geomorphological and ecological responses. In this study, they are used for estimating environmental flow requirements. We applied a Pseudo-two-dimensional (2D) model based on the one-dimensional (1D) HEC-RAS model and an in-house 2D (FLOW-R2D) hydrodynamic model to a section of river for several flows in respect of summer conditions of the study reach, and compared the results derived from the models in terms of water depths and velocities as well as habitat predictions in terms of weighted usable area (WUA). In general, 2D models are more promising in habitat studies since they quantify spatial variations and combinations of flow patterns important to stream flora and fauna in a higher detail than the 1D models. Relationships between WUA and discharge for the two models were examined, to compare the similarity as well as the magnitude of predictions over the modelled discharge range. The models predicted differences in the location of maxima and changes in variation of velocity and water depth. Finally, differences in spatial distribution (in terms of suitability indices and WUA) between the Pseudo-2D and the fully 2D modelling results can be considerable on a cell-by-cell basis.

scholarly journals A monolithic algorithm for the flow simulation of flexible flapping wings

2019 ◽  
Vol 11 ◽  
pp. 175682931984612 ◽  
Author(s):  
Tao Yang ◽  
Mingjun Wei ◽  
Kun Jia ◽  
James Chen
Keyword(s):  
Three Dimensional ◽  
Flow Simulation ◽  
Flapping Wings ◽  
Rigid Sphere ◽  
Two Dimensional ◽  
Unified Framework ◽  
Fluid Structure ◽  
A Cell ◽  
Three Dimensional Configuration ◽  
The Impact

It has been a challenge to simulate flexible flapping wings or other three-dimensional problems involving strong fluid–structure interactions. Solving a unified fluid–solid system in a monolithic manner improves both numerical stability and efficiency. The current algorithm considered a three-dimensional extension of an earlier work which formulated two-dimensional fluid–structure interaction monolithically under a unified framework for both fluids and solids. As the approach is extended from a two-dimensional to a three-dimensional configuration, a cell division technique and the associated projection process become necessary and are illustrated here. Two benchmark cases, a floppy viscoelastic particle in shear flow and a flow passing a rigid sphere, are simulated for validation. Finally, the three-dimensional monolithic algorithm is applied to study a micro-air vehicle with flexible flapping wings in a forward flight at different angles of attack. The simulation shows the impact from the angle of attack on wing deformation, wake vortex structures, and the overall aerodynamic performance.

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