Highly resolved pulsatile flows through prosthetic heart valves using the entropic lattice-Boltzmann method

2014 ◽  
Vol 754 ◽  
pp. 122-160 ◽  
Author(s):  
B. Min Yun ◽  
L. P. Dasi ◽  
C. K. Aidun ◽  
A. P. Yoganathan
Keyword(s):  
Lattice Boltzmann Method ◽  
Pulsatile Flow ◽  
Lattice Boltzmann ◽  
Heart Valves ◽  
Prosthetic Heart Valves ◽  
Spatiotemporal Resolution ◽  
Jude Medical ◽  
High Spatiotemporal Resolution ◽  
Flow Through ◽  
Boltzmann Method

AbstractProsthetic heart valves have been widely used to replace diseased or defective native heart valves. Flow through bileaflet mechanical heart valves (BMHVs) have previously demonstrated complex phenomena in the vicinity of the valve owing to the presence of two rigid leaflets. This study aims to accurately capture the complex flow dynamics for pulsatile flow through a 23 mm St Jude Medical (SJM) Regent™ BMHV. The lattice-Boltzmann method (LBM) is used to simulate pulsatile flow through the valve with the inclusion of reverse leakage flow at very high spatiotemporal resolution that can capture fine details in the pulsatile BMHV flow field. For higher-Reynolds-number flows, this high spatiotemporal resolution captures features that have not been observed in previous coarse resolution studies. In addition, the simulations are able to capture with detail the features of leaflet closing and the asymmetric b-datum leakage jet during mid-diastole. Novel flow physics are visualized and discussed along with quantification of turbulent features of this flow, which is made possible by this parallelized numerical method.

Computational modelling of flow through prosthetic heart valves using the entropic lattice-Boltzmann method

2014 ◽  
Vol 743 ◽  
pp. 170-201 ◽  
Author(s):  
B. Min Yun ◽  
L. P. Dasi ◽  
C. K. Aidun ◽  
A. P. Yoganathan
Keyword(s):  
Lattice Boltzmann Method ◽  
Numerical Method ◽  
Pulsatile Flow ◽  
Lattice Boltzmann ◽  
Heart Valves ◽  
Prosthetic Heart Valves ◽  
Flow Through ◽  
Leaflet Motion ◽  
High Reynolds ◽  
Boltzmann Method

AbstractPrevious clinical, in vitro experimental and in silico simulation studies have shown the complex dynamics of flow through prosthetic heart valves. In the case of bileaflet mechanical heart valves (BMHVs), complex flow phenomena are observed due to the presence of two rigid leaflets. A numerical method for this type of study must be able to accurately simulate pulsatile flow through BMHVs with the inclusion of leaflet motion and high-Reynolds-number flow modelling. Consequently, this study aims at validating a numerical method that captures the flow dynamics for pulsatile flow through a BMHV. A $23~ \mbox{mm}$ St. Jude Medical (SJM) Regent™ valve is selected for use in both the experiments and numerical simulations. The entropic lattice-Boltzmann method is used to simulate pulsatile flow through the valve with the inclusion of reverse leakage flow, while prescribing the flowrate and leaflet motion from experimental data. The numerical simulations are compared against experimental digital particle image velocimetry (DPIV) results from a previous study for validation. The numerical method is shown to match well with the experimental results quantitatively as well as qualitatively. Simulations are performed with efficient parallel processing at very high spatiotemporal resolution that can capture the finest details in the pulsatile BMHV flow field. This study validates the lattice-Boltzmann method as suitable for simulating pulsatile, high-Reynolds-number flows through prosthetic devices for use in future research.

scholarly journals Blood Damage Through a Bileaflet Mechanical Heart Valve: A Quantitative Computational Study Using a Multiscale Suspension Flow Solver

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
B. Min Yun ◽  
Cyrus K. Aidun ◽  
Ajit P. Yoganathan
Keyword(s):  
Numerical Method ◽  
Heart Valves ◽  
Computational Study ◽  
Mechanical Heart Valve ◽  
Complex Flow ◽  
Damage Potential ◽  
Spatiotemporal Resolution ◽  
Jude Medical ◽  
Blood Damage ◽  
Flow Through

Bileaflet mechanical heart valves (BMHVs) are among the most popular prostheses to replace defective native valves. However, complex flow phenomena caused by the prosthesis are thought to induce serious thromboembolic complications. This study aims at employing a novel multiscale numerical method that models realistic sized suspended platelets for assessing blood damage potential in flow through BMHVs. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow through a 23 mm St. Jude Medical (SJM) Regent™ valve in the aortic position at very high spatiotemporal resolution with the presence of thousands of suspended platelets. Platelet damage is modeled for both the systolic and diastolic phases of the cardiac cycle. No platelets exceed activation thresholds for any of the simulations. Platelet damage is determined to be particularly high for suspended elements trapped in recirculation zones, which suggests a shift of focus in blood damage studies away from instantaneous flow fields and toward high flow mixing regions. In the diastolic phase, leakage flow through the b-datum gap is shown to cause highest damage to platelets. This multiscale numerical method may be used as a generic solver for evaluating blood damage in other cardiovascular flows and devices.

Lattice-Boltzmann Method for Macroscopic Porous Media Modeling

1998 ◽  
Vol 09 (08) ◽  
pp. 1491-1503 ◽  
Author(s):  
David M. Freed
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Inertial Effects ◽  
Simulation Region ◽  
Flow Through ◽  
Previous Algorithm ◽  
Validation Tests ◽  
Boltzmann Method

An extension to the basic lattice-BGK algorithm is presented for modeling a simulation region as a porous medium. The method recovers flow through a resistance field with arbitrary values of the resistance tensor components. Corrections to a previous algorithm are identified. Simple validation tests are performed which verify the accuracy of the method, and demonstrate that inertial effects give a deviation from Darcy's law for nominal simulation velocities.

Simulation of flow through bead packs using the lattice Boltzmann method

1998 ◽  
Vol 10 (1) ◽  
pp. 60-74 ◽  
Author(s):  
R. S. Maier ◽  
D. M. Kroll ◽  
Y. E. Kutsovsky ◽  
H. T. Davis ◽  
R. S. Bernard
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Flow Through ◽  
Boltzmann Method

Simulation of High Knudsen Number Gas Flows in Nanochannels via the Lattice Boltzmann Method

2011 ◽  
Vol 403-408 ◽  
pp. 5318-5323
Author(s):  
A.H. Meghdadi Isfahani ◽  
A. Soleimani ◽  
A. Homayoon
Keyword(s):  
Lattice Boltzmann Method ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Numerical Data ◽  
Gas Flows ◽  
Wide Range ◽  
Flow Through ◽  
Boltzmann Method ◽  
Slip Transition ◽  
Pressure Driven Flow

Using a modified Lattice Boltzmann Method (LBM), pressure driven flow through micro and nano channels has been modeled. Based on the improving of the dynamic viscosity, an effective relaxation time formulation is proposed which is able to simulate wide range of Knudsen number, Kn, covering the slip, transition and to some extend the free molecular regimes. The results agree very well with exiting empirical and numerical data.

Simulation of Sound Generation by Flow over a Cavity with the Lattice Boltzmann Method

2012 ◽  
Vol 184-185 ◽  
pp. 456-459
Author(s):  
Shan Ling Han ◽  
Li Sha Yu ◽  
Gui Shen Wang ◽  
Qing Liang Zeng
Keyword(s):  
Shear Layer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Fluid Flows ◽  
Cavity Resonance ◽  
Aerodynamic Noise ◽  
Mesoscopic Models ◽  
Flow Through ◽  
Flow Over A Cavity ◽  
Boltzmann Method

The fluid flows and its related aerodynamic noise are very common in the nature and the engineering fieds. Lattice Boltzmann Method (LBM), which is based on the mesoscopic models, is a new CFD approach. It has the congenital superiority and the inestimable development potential in the simulation of complex fluid flow. Referring to the experimental results provided by NASA/CP 2004-212954, the aerodynamic noise produced by the flow through a cavity is simulated by the lattice Boltzmann method. The results had vividly demonstrated the shear layer oscillations, the couple between the shear layer oscillations and cavity resonance pattern. This simulation has discovered that the shear layer oscillation is the main reason for the production of cavity aerodynamic noise. The simulation results are consistent with the NASA experiment data.

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