Fluid-structure interaction analysis on the effects of vessel material properties on blood flow characteristics in stenosed arteries under axial rotation

2011 ◽  
Vol 23 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Seong Wook Cho ◽  
Seung Wook Kim ◽  
Moon Hyun Sung ◽  
Kyoung Chul Ro ◽  
Hong Sun Ryou
Author(s):  
Esfandyar Kouhi ◽  
Yos Morsi

In this paper the fluid structure interaction in stentless aortic heart valve during acceleration phase was performed successfully using the commercial ANSYS/CFX package. The aim is to provide unidirectional coupling FSI analysis of physiological blood flow within an anatomically corrected numerical model of stentless aortic valve. Pulsatile, Newtonian, and turbulent blood flow rheology at aortic level was applied to fluid domain. The proposed structural prosthesis had a novel multi thickness leaflet design decreased from aortic root down to free age surface. An appropriate interpolation scheme used to import the fluid pressure on the structure at their interface. The prosthesis deformations over the acceleration time showed bending dominant characteristic at early stages of the cardiac cycle. More stretching and flattening observed in the rest of the times steps. The multi axial Von Mises stress data analysis was validated with experimental data which confirmed the initial design of the prosthesis.


2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Kittisak Koombua ◽  
Ramana M. Pidaparti

Better understanding of stresses and flow characteristics in the human airways is very important for many clinical applications such as aerosol drug therapy, inhalation toxicology, and airway remodeling process. The bifurcation geometry of airway generations 3 to 5 based on the ICRP tracheobronchial model was chosen to analyze the flow characteristics and stresses during inhalation. A computational model was developed to investigate the airway tissue flexibility effect on stresses and flow characteristics in the airways. The finite-element method with the fluid-structure interaction analysis was employed to investigate the transient responses of the flow characteristics and stresses in the airways during inhalation. The simulation results showed that tissue flexibility affected the maximum airflow velocity, airway pressure, and wall shear stress about 2%, 7%, and 6%, respectively. The simulation results also showed that the differences between the orthotropic and isotropic material models on the airway stresses were in the ranges of 25–52%. The results from the present study suggest that it is very important to incorporate the orthotropic tissue properties into a computational model for studying flow characteristics and stresses in the airways.


2005 ◽  
Vol 2005 (1) ◽  
pp. 585-588 ◽  
Author(s):  
Azin Amini ◽  
Maziar Mahzari ◽  
Erik Bollaert ◽  
Anton Schleiss

ABSTRACT The most important aspect of the ongoing research project is to develop numerical coupled hydraulic-structural analysis models of oil containment booms. This should be later applicable for investigation of the efficiency limits of a new system of oil spill containment booms called Cavalli system. This system consists of surrounding the oil slick with a special boom and protecting it against waves and currents. It provides the possibility to divide the encircled area in several smaller circles and to increase the thickness of the oil slick inside. The whole system consists of a two-phase fluid (oil and water) and a boom that should be structurally stable for the pressure loads imposed by the fluids. It is finally important to evaluate the behaviour of the flexible skirt under different wave and current conditions, as almost all of existing research in the field have been undertaken for rigid barriers. To assess the behaviour of a flexible barrier fluid-structure interaction analysis is to be conducted. The problem is considered as a fluid-structure interaction problem as the boom usually undergoes large deformations and rotations, which modifies the flow characteristics during operation that is not the case for a rigid boom.


Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 300 ◽  
Author(s):  
Zhen-hao Lin ◽  
Xiao-juan Li ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian

In this paper, the effect of membrane features on flow characteristics in the microfluidic passive valve (MPV) and the membrane behavior against fluid flow are studied using the fluid-structure interaction (FSI) analysis. Firstly, the microvalve model with different numbers of microholes and pitches of microholes are designed to investigate the flow rate of the MPV. The result shows that the number of microholes on the membrane has a significant impact on the flow rate of the MPV, while the pitch of microholes has little effect on it. The constant flow rate maintained by the microvalve (the number of microholes n = 4) is 5.75 mL/min, and the threshold pressure to achieve the flow rate is 4 kPa. Secondly, the behavior of the membrane against the fluid flow is analyzed. The result shows that as the inlet pressure increases, the flow resistance of the MPV increases rapidly, and the deformation of the membrane gradually becomes stable. Finally, the effect of the membrane material on the flow rate and the deformation of the membrane are studied. The result shows that changes in the material properties of the membrane cause a decrease in the amount of deformation in all stages the all positions of the membrane. This work may provide valuable guidance for the optimization of microfluidic passive valve in microfluidic system.


2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Abdalla Mohamed AlAmiri

The current numerical investigation tackles the fluid-structure interaction in a blood vessel subjected to a prescribed heating scheme on tumor tissues under thermal therapy. A pulsating incompressible laminar blood flow was employed to examine its impact on the flow and temperature distribution within the blood vessel. In addition, the arterial wall was modeled using the volume-averaged porous media theory. The motion of a continuous and deformable arterial wall can be described by a continuous displacement field resulting from blood pressure acting on the tissue. Moreover, discretization of the transport equations was achieved using a finite element scheme based on the Galerkin method of weighted residuals. The numerical results were validated by comparing them against documented studies in the literature. Three various heating schemes were considered: constant temperature, constant wall flux, and a step-wise heat flux. The first two uniform schemes were found to exhibit large temperature variation within the tumor, which might affect the surrounding healthy tissues. Meanwhile, larger vessels and flexible arterial wall models render higher variation of the temperature within the treated tumor, owing to the enhanced mixing in the vicinity of the bottom wall.


Author(s):  
Alejandro Roldán ◽  
Nancy Sweitzer ◽  
Tim Osswald ◽  
Naomi Chesler

Modeling pulsatile flow past heart valves remains a relatively unexplored but critical area. Due to the geometric complexity and the interaction between the flowing blood and the heart valve leaflets, existing numerical techniques that require domain discretization, such as finite element methods or finite difference techniques, cannot fully represent the moving and deforming boundaries present in an operating valve. Our aim is to develop a technique to model the flow through heart valves which includes the interaction between the blood flow and the valve leaflets using the radial functions method (RFM). The RFM is a meshless technique that fully accounts for moving and deforming surfaces and thus is well suited to model the blood flow and its interaction with leaflet motion. Here we present a 2D fluid structure interaction (FSI) model of the blood flow through a bileaflet mechanical heart valve (MHV).


Perfusion ◽  
2021 ◽  
pp. 026765912199854
Author(s):  
Mohammad Javad Ghasemi Pour ◽  
Kamran Hassani ◽  
Morteza Khayat ◽  
Shahram Etemadi Haghighi

Background and objectives: Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method. Methods: The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain. Results: The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg. The validation of the predicted results was also conducted using existing literature. Conclusions: We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.


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