PoojaJhunjhunwala¹, P.M. Padole², S.B. Thombre³

Molecular & Cellular Biomechanics, Vol.13, No.1, pp. 1-21, 2016, DOI:10.3970/mcb.2016.013.001

Abstract This paper presents Computational fluid dynamic (CFD) analysis of blood flow in three different 3-D models of left coronary artery (LCA). A comparative study of flow parameters (pressure distribution, velocity distribution and wall shear stress) in each of the models is done for a non-Newtonian (Carreau) as well as the Newtonian nature of blood viscosity over a complete cardiac cycle. The difference between these two types of behavior of blood is studied for both transient and steady states of flow. Additionally, flow parameters are compared for steady and transient boundary conditions considering blood as non-Newtonian fluid. The study shows that… More >

Xi Zhao^∗, Youjun Liu^∗,†, Wenxin Wang^∗

Molecular & Cellular Biomechanics, Vol.12, No.1, pp. 49-66, 2015, DOI:10.3970/mcb.2015.012.049

Abstract Purpose: Sequential graft and Y-type graft are two different surgical procedures in coronary artery bypass grafting (CABG). The hemodynamic environment of them are different, that may cause different short-term surgical result and long-term patency. In this study, the short-term and long-term result of sequential and Y-type graft was discussed by comparing the hemodynamics of them. Materials and Methods: Two postoperative 3-dimensional (3D) models were built by applying different graft on a patient-specific 3D model with serious stenosis. Then zero-dimensional (0D)/3D coupled simulation was carried out by coupling the postoperative 3D models with a 0D lumped parameter model of the cardiovascular… More >

E. Shaik^∗, K.A. Hoffmann^∗, J-F. Dietiker^∗

Molecular & Cellular Biomechanics, Vol.4, No.1, pp. 41-54, 2007, DOI:10.3970/mcb.2007.004.041

Abstract A potential interaction between the local hemodynamics and the artery wall response has been suggested for vascular graft failure by intimal hyperplasia (IH). Among the various hemodynamic factors, wall shear stress has been implicated as the primary factor responsible for the development of IH. In order to explore the role of hemodynamics in the formation of IH in end-to-side anastomosis, computational fluid dynamics is employed. To validate the numerical simulations, comparisons with existing experimental data are performed for both steady and pulsatile flows. Generally, good agreement is observed with the velocity profiles whereas some discrepancies are found in wall shear… More >

Biao Wang^1,*, Yongjian Yang¹, Hesong Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 649-678, 2019, DOI:10.31614/cmes.2019.05671

Abstract To calculate the diffusion law of chaff cloud launched by aircraft, taking rectangular chaff as an example, the diffusion model of chaff cloud is established in this paper. Firstly, the coordinate systems of chaff are defined and the motion model of chaff is established. The motion model mainly includes chaff motion equation and rotation equation, which are obtained by combining the aerodynamic moment and aerodynamic damping. Then, the influence of multi-chaff aerodynamic interference on the movement of chaff is analyzed. Finally, considering the influence of overlap area between chaffs and chaff spacing on the aerodynamic coefficients, the multi-chaff motion model… More >

Wenxin Wang^1,2, Dalin Tang², Boyan Mao¹, Bao Li¹, Xi Zhao³, Jian Liu⁴, Youjun Liu^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 163-173, 2018, DOI: 10.31614/cmes.2018.04219

Abstract Fractional flow reserve (FFR) is the gold standard to identify individual stenosis causing myocardial ischemia in catheter laboratory. The purpose of this study is to present a fast simulation method to estimate FFR value of a coronary artery, which can evaluate the performance of vascular stenosis, based on resistance boundary conditions. A patient-specific 3-dimensional (3D) model of the left coronary system with intermediate diameter stenosis was reconstructed based on the CTA images. The resistance boundary conditions used to simulate the coronary microcirculation were computed based on anatomical reconstruction of coronary 3D model. This study was performed by coupling the 3D… More >

Xudong Liu¹, Yunhan Cai¹, Bing Jia², Shengzhang Wang^1,*, Guanghong Ding¹

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 215-228, 2018, DOI: 10.31614/cmes.2018.04158

Abstract Our study evaluated the hemodynamic performance of an axial flow blood pump surgically implanted in idealized total cavopulmonary connection (TCPC) models. This blood pump was designed to augment pressure from the inferior vena cava (IVC) to the pulmonary circulation. Two Fontan procedures with single and bilateral superior vena cava (SVC) were compared to fit the mechanical supported TCPC physiologies. Computational fluid dynamics (CFD) analyses of two Pump-TCPC models were performed in the analyses. Pressure-flow characteristics, energy efficiency, fluid streamlines, hemolysis and thrombosis analyses were implemented. Numerical simulations indicate that the pump produces pressure generations of 1 mm to 24 mm… More >

Guangliang Pan¹, Yu Chang^1,*, Mingrui Fu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.2, pp. 199-213, 2018, DOI: 10.31614/cmes.2018.04080

Abstract Patients with extracorporeal membrane oxygenation still suffer from high rates of complication that linked to the flow field within the blood pump. So it is essential to optimise the geometry of the pump. The specification of shroud design is arguably the necessary design parameter in the centrifugal pump. However, the hemodynamic performances of the different shroud designs have not been studied extensively. In this study, ten different shroud designs were made and divided into two groups as the different covering locations (A: Covering the blade leading edge, B: Covering the blade trailing edge). In every group, six shroud designs with… More >

Jun Huang^1,2, Chaopu Zhang¹, Song Xiang², Liu Yang¹, Mingxu Yi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 315-330, 2015, DOI:10.3970/cmes.2015.108.315

Abstract In order to accurately predict the aerodynamic noise of the propeller, a hybrid method combining Computational Fluid Dynamics (CFD) method with Boundary Element Method (BEM) is developed in this paper. The calculation includes two steps: firstly, the unsteady viscous flow around the propeller is calculated using the CFD method to acquire the noise source information; secondly, the radiated sound pressure is calculated using BEM method in the frequency domain. In comparison with the experimental results from wind tunnel, the calculated results of aerodynamic performance are rather desirable. The simulation and experimental results of aerodynamic noise are well fitted. The directivity… More >

Jason F. Hammond¹, Elizabeth J. Stewart², John G. Younger³, Michael J.Solomon², David M. Bortz^4,5

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.3, pp. 295-340, 2014, DOI:10.32604/cmes.2014.098.295

Abstract The overall goal of this work is to develop a numerical simulation which correctly describes a bacterial biofilm fluid-structure interaction and separation process. In this, the first of a two-part effort, we fully develop a convergent scheme and provide numerical evidence for the method order as well as a full 3D separation simulation. We use an immersed boundary-based method (IBM) to model and simulate a biofilm with density and viscosity values different from than that of the surrounding fluid. The simulation also includes breakable springs connecting the bacteria in the biofilm which allows the inclusion of erosion and detachment into… More >

L.Q. Moreira¹, F.P. Mariano², A. Silveira-Neto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.75, No.2, pp. 113-140, 2011, DOI:10.3970/cmes.2011.075.113

Abstract Turbulence in fluid flow is one of the most challenging problems in classical physics. It is a very important research problem because of its numerous implications, such as industrial applications that involve processes using mixtures of components, heat transfer and lubrication and injection of fuel into the combustion chambers and propulsion systems of airplanes. Turbulence in flow presents characteristics that are fully nonlinear and that occur at high Reynolds numbers. Because of the nonlinear nature of turbulent flow, an increase in the Reynolds number implies an increase in the Kolmogorov wave numbers, and the flow spectrum becomes larger in both… More >