scholarly journals SIMULATION OF PULSATILE FLOW THROUGH ARTERIAL TREE MODELS

2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Igor Pires dos Santos ◽  
Ruy Freitas Reis ◽  
Rafael Alves Bonfim de Queiroz
Keyword(s):  
Flow Simulation ◽  
Multiple Objects ◽  
Arterial Tree ◽  
Wave Characteristics ◽  
Analytical Scheme ◽  
Computational Environment ◽  
Compact Class ◽  
Local Wave ◽  
Tree Models ◽  
Flow Through

In this work, an analytical scheme for evaluating the local wave characteristics of flow and pressure in 1D arterial tree’s models is implemented. An interactive computational environment was developed to simulate this scheme. The presented environment contains a compact class structure to enable the iteration and visualization of multiple objects. The results obtained are consistent with those from literature. The software developed provides the visualization of a blood flow simulation through a simple user interface.

Computation of Flow Through a Three-Dimensional Periodic Array of Porous Structures by a Parallel Immersed-Boundary Method

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Zhenglun Alan Wei ◽  
Zhongquan Charlie Zheng ◽  
Xiaofan Yang
Keyword(s):  
Porous Media ◽  
Parallel Implementation ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Periodic Array ◽  
Immersed Boundary ◽  
Navier Stokes Equation ◽  
Flow Through ◽  
Ib Method

A parallel implementation of an immersed-boundary (IB) method is presented for low Reynolds number flow simulations in a representative elementary volume (REV) of porous media that are composed of a periodic array of regularly arranged structures. The material of the structure in the REV can be solid (impermeable) or microporous (permeable). Flows both outside and inside the microporous media are computed simultaneously by using an IB method to solve a combination of the Navier–Stokes equation (outside the microporous medium) and the Zwikker–Kosten equation (inside the microporous medium). The numerical simulation is firstly validated using flow through the REVs of impermeable structures, including square rods, circular rods, cubes, and spheres. The resultant pressure gradient over the REVs is compared with analytical solutions of the Ergun equation or Darcy–Forchheimer law. The good agreements demonstrate the validity of the numerical method to simulate the macroscopic flow behavior in porous media. In addition, with the assistance of a scientific parallel computational library, PETSc, good parallel performances are achieved. Finally, the IB method is extended to simulate species transport by coupling with the REV flow simulation. The species sorption behaviors in an REV with impermeable/solid and permeable/microporous materials are then studied.

Convective exchange in oscillatory flow through bronchial-tree models

1982 ◽  
Vol 53 (4) ◽  
pp. 1023-1033 ◽  
Author(s):  
P. W. Scherer ◽  
F. R. Haselton
Keyword(s):  
Bronchial Tree ◽  
Convective Transport ◽  
Physical Models ◽  
High Frequency Ventilation ◽  
Laminar And Turbulent Flow ◽  
Frequency Ventilation ◽  
Tree Models ◽  
Physical Insight ◽  
Flow Through ◽  
Convective Exchange

An important and previously unappreciated longitudinal convective-transport mechanism has been shown to operate in tube-bifurcation models geometrically and dynamically similar to upper and lower regions of the bronchial tree. The mechanism depends on the differences in shape that exist between inspiratory and expiratory velocity profiles in laminar and turbulent flow within the bronchial tubes and provides new and deeper physical insight into the flow of gases, aerosol particles, and heat in the airways. By use of dimensional analysis to relate the flows in the physical models to those in the real bronchial tree, the mechanism is shown to be important in normal breathing of gases and aerosols and is likely to be important also in high-frequency ventilation.

Cavitating Flow Simulation in a Closed Pump Sump by Two-Fluid Model and Its PIV Verification

2003 ◽  
Author(s):  
Yu Xu ◽  
Yulin Wu ◽  
Shuhong Liu ◽  
Yong Li
Keyword(s):  
Fluid Model ◽  
Flow Simulation ◽  
Cavitating Flow ◽  
Governing Equations ◽  
Two Phase ◽  
Averaged Equations ◽  
Flow Through ◽  
Pump Sump ◽  
Two Fluid Model ◽  
Two Fluid

In this paper, the two-fluid model was adopted to analyze the cavitating flow. Based on Boltzmann equation, governing equations for two-phase cavitating flow were obtained by using the microscopic kinetic theory, in which the equation terms for mass and momentum transportations can be obtained directly. Then the RNG k–ε–kg turbulence model, that is RNG k–ε model for the liquid phase and kg model for the cavity phase, was used to close the Reynolds time-averaged equations. According to the governing equations above, the simulation of the two-phase cavitating flow through a closed pump sump has been carried out. The calculated results have been compared with a PIV experiment. Good agreement exhibited.

Numerical and Experimental Simulation of Two-Phase Tsunami Flow Through Buildings with Openings

2015 ◽  
Vol 09 (03) ◽  
pp. 1550007 ◽  
Author(s):  
Hartana ◽  
Keisuke Murakami
Keyword(s):  
Flow Simulation ◽  
Experimental Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Building Models ◽  
Flow Through ◽  
Heavy Loads ◽  
Complex Phenomena ◽  
Uplift Forces ◽  
Good Agreement

During tsunami action on a structure, the structure is subjected to heavy loads with complex phenomena which include the interactions among tsunami, structure and air. In order to mitigate tsunami damages on structures, it is important to understand the characteristics of tsunami hydraulic loads acting on the structures with taking into account the above interactions. In the present study, the characteristics of tsunami forces on a building structure are investigated using a two-phase flow model. Two types of building models, a building without openings and with openings, were dealt with; and the effects of openings on the building under the tsunami hydraulic loads are examined. The simulation results were compared with the results obtained from one-phase flow simulation, and also verified with experimental data. The numerical results show good agreement with the measured ones. Furthermore, the effects of air taken into the flow and opening configuration on the characteristics of pressures and uplift forces were also discussed.

Topological rearrangements and flow simulation of dry ordered foams

2014 ◽  
Vol 05 (supp01) ◽  
pp. 1441007 ◽  
Author(s):  
J. S. Espinoza Ortiz ◽  
H. Belich ◽  
M. T. D. Orlando ◽  
R. E. Lagos
Keyword(s):  
Strain Rate ◽  
Critical Behavior ◽  
Potts Model ◽  
Driving Force ◽  
Flow Simulation ◽  
Two Dimensional ◽  
Fluid Regime ◽  
Cellular Potts Model ◽  
Flow Through ◽  
Liquid Foam

Flow through a narrow bent channel may induce topological rearrangements in a two-dimensional monodispersed dry liquid foam. We use the Cellular Potts Model to simulate a foam under a variable driving force in order to investigate the strain-rate response from these rearrangements. We observe a set of foams' behaviors ranging from elastic, viscoelastic to fluid regime. Bubble's topological rearrangements are localized and their cumulative rearrangements change linearly with time, thus nonavalanches critical behavior is found. The strain-rate affects the rate of topological rearrangements, its dependence on the drag force is nonlinear, obeying a Herschel–Bulkley-like relationship below the foam's flow point.

scholarly journals A CFD ANALYSIS IN SOLIDWORKS FLOW SIMULATION FOR TWO MIXING FLUIDS WITH DIFFERENT TEMPERATURES IN NOZZLES

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
IONEL OLARU
Keyword(s):  
Complex Analysis ◽  
Flow Simulation ◽  
Additional Stress ◽  
Fluid Temperature ◽  
Electronic Components ◽  
Temperature Changes ◽  
Different Temperatures ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Mechanical Elements

<p>The heat can have a direct impact on the mechanical elements by creating deformations and by causing the induction of additional stress in them. In designing of the heat exchangers or for the electronic components, the temperature changes for structural analysis as well as structural performance of thermal impact for the entire element must be analyzed. The study from this paper proposes an analysis and a simulation of flow through the convergent-divergent nozzle type to optimize the inlet of warm fluid to have minimum impact on the nozzle walls This analysis will be performed with a computer program specialized in complex analysis of Computational Fluid Dynamics (CFD), which will also take into account the fluid temperature and its influence throughout the system.</p>

Shape Optimization of Power Plant Ducting Using CFD

2008 ◽  
Author(s):  
Ramesh Avvari ◽  
Sreenivas Jayanti ◽  
S. Gowrisankar
Keyword(s):  
Power Plant ◽  
Pressure Drop ◽  
Cross Section ◽  
High Velocity ◽  
Flow Simulation ◽  
Higher Power ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
The Cross ◽  
Flow Maldistribution

Power plant ducting generally designed with simple shapes has to undergo many changes of shape to accommodate interfacing equipment associated with plant operation leading to higher pressure drop, higher power consumption and flow maldistribution zones having higher or lower velocities. To redress this situation, baffles, guide vanes and other internals are used to streamline the flow through ducts, especially in bends. A basic disadvantage in coal fired plants of using baffles is that they get punctured / eroded due to impact of high velocity ash particles in flue gas ducting, and the effectiveness of baffles is lost in short duration. To overcome the above disadvantages, a new method is developed to change the shape of the duct in such a way that a more streamlined flow is maintained across any cross section. The velocity profile, obtained using computational fluid dynamics (CFD) calculations, across the cross-section is examined at several locations along the duct. Wherever high velocity compared to average velocity is found, the cross-section is increased and where the velocity is low, the cross-section is reduced. A new grid is created through the revised cross-section and a fresh CFD analysis is made to identify zones of flow maldistribution. The flow simulation is done in an iterative manner, alternately calculating the flow domain and modifying the local cross-section based on the local velocity distribution. The method has been found to be more robust and led, after a few iterations, to a shape of the duct which resulted in a significant reduction in the pressure drop without using any baffles or inserts.

scholarly journals Blood Flow Simulation in Patient-Specific Segmented Hepatic Arterial Tree

IRBM ◽  
2017 ◽  
Vol 38 (3) ◽  
pp. 120-126
Author(s):  
C. Simoncini ◽  
Y. Rolland ◽  
V. Morgenthaler ◽  
K. Jurczuk ◽  
H. Saint-Jalmes ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Simulation ◽  
Patient Specific ◽  
Arterial Tree ◽  
Blood Flow Simulation

scholarly journals THE FLUID FLOW SIMULATION THROUGH TO A VENTURI NOZZLE

2016 ◽  
Vol 19 (1) ◽  
Author(s):  
IONEL OLARU
Keyword(s):  
Fluid Flow ◽  
Metal Cutting ◽  
Flow Simulation ◽  
Cooling Systems ◽  
Fluid Jets ◽  
Cutting Zone ◽  
Flow Through ◽  
The Impact ◽  
Venturi Nozzle ◽  
Flow Study

<p>In this work it was performed a fluid flow study of cooling systems for metal cutting. The study of forces resulting from the impact of fluid jets and when fluids are diverted round through the nozzle involves the application of pressure forces. The forces are determined by calculating the change of momentum of the flowing fluids. It was performed a simulation of the flow through a nozzle commonly used for pressure cooling of the cutting zone.</p>

scholarly journals Data Analysis of Two-Phase Flow Simulation Experiment of Array Optical Fiber and Array Resistance Probe

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1420
Author(s):  
Shuaifei Cui ◽  
Junfeng Liu ◽  
Kui Li ◽  
Qinze Li
Keyword(s):  
Optical Fiber ◽  
Flow Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Optical Fiber Probes ◽  
Flow Through ◽  
Water Cut ◽  
Domestic Design

To solve the problem that traditional single-probe instruments cannot accurately measure the gas and water holdup, the domestic design of the array holdup measuring instrument Array of Optical and Resistance Tool (AORT), composed of five sets of optical fiber probes and five sets of resistance probes, is carried out in both gas–water and oil–water. Simulated measurement experiments were conducted under different water cut in phase flow. Through the analysis of the experimental data, the response relationship between the optical fiber probe and the resistance probe of the AORT instrument in different fluids was obtained. Then, the data under different conditions of fluid, flowrate and water cut in the experiment were compared by drawing. Interpolation algorithm was used to perform two-maintenance holdup imaging, and finally the holdup image was compared with the pictures of the flow in the pipe recorded during the experiment. The results show that the resistance probe has a better response under low water cut conditions, and the optical fiber probe has a better response under high gas cut conditions, which is consistent with the theoretical analysis. The imaging diagram and the flow pattern in the pipe during the experiment are in good agreement. It can be seen that the accuracy of the holdup measured by the AORT instrument under the test conditions is verified, and can provide technical support for further carrying out the measurement and interpretation of the holdup in future, as well as the improvement of the instrument and on-site testing.

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