Fithry Mohd Amir^*, Mohd Zamri Yusoff, Saiful Hasmady Abu Hassan

Frontiers in Heat and Mass Transfer, Vol.18, pp. 1-15, 2022, DOI:10.5098/hmt.18.27

Abstract Nanofluid film on a horizontal tube is investigated numerically on the circular and multi-faceted cylinder. The fluid flow characteristics, including film thickness, shear stress, and thermal performance, are observed and analyzed. Fluid film on the circular surface is typical in many engineering applications, but the study of nanofluid film on non-circular surface is deficient in literature. The study provides a numerical model of a multi-faceted cylinder to simulate the nanofluid film on the non-circular surfaces using a volume of fluid (VOF) method. The ratio of Brownian motion to thermophoretic diffusion, N_BT developed along the film thickness in phases, in which… More >

Suraj Shembekar^*, Dhananjay Zodpe, Pramod Padole

Molecular & Cellular Biomechanics, Vol.19, No.4, pp. 165-175, 2022, DOI:10.32604/mcb.2022.021513

Abstract Arteriovenous fistula (AVF) is the endorsed method of vascular access for hemodialysis in end-stage renal disease (ESRD). However, more than 60% of AVF fail to mature for hemodialysis. Intimal hyperplasia leads to stenosis is the primary cause of fistula failure. Wall shear stress (WSS) is one of the important parameters that enact a crucial role in building of intimal hyperplasia. The prime purpose of this research work is to investigate the effect of anastomosis angle on WSS, pressure drop, venous outflow rate and identify the optimal angle of anastomosis of AVF, so that it helps to standardize the surgical technique.… More >

Qingzhuo Chi¹, Huimin Chen¹, Shiqi Yang¹, Lizhong Mu^1,*, Changjin Ji², Ying He¹, Yong Luan³

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.1, pp. 31-47, 2022, DOI:10.32604/cmes.2022.018286

Abstract Cardiovascular computational fluid dynamics (CFD) based on patient-specific modeling is increasingly used to predict changes in hemodynamic parameters before or after surgery/interventional treatment for aortic dissection (AD). This study investigated the effects of flow boundary conditions (BCs) on patient-specific aortic hemodynamics. We compared the changes in hemodynamic parameters in a type A dissection model and normal aortic model under different BCs: inflow from the auxiliary and truncated structures at aortic valve, pressure control and Windkessel model outflow conditions, and steady and unsteady inflow conditions. The auxiliary entrance remarkably enhanced the physiological authenticity of numerical simulations of flow in the ascending… More >

Mohamad Shukri Zakaria^1,*, Haslina Abdullah², Azmi Nordin¹, Syazwati Ahmad Zaki¹

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.1, pp. 171-179, 2021, DOI:10.32604/fdmp.2021.010974

Abstract This study deals with the interaction of blood flow with the wall aorta, i.e., the boundary of the main artery that transports blood in the human body. The problem is addressed in the framework of computational fluid dynamics complemented with (FSI), i.e., a fluid-structure interaction model. Two fundamental types of wall are considered, namely a flexible and a rigid boundary. The resulting hemodynamic flows are carefully compared in order to determine which boundary condition is more effective in reproducing reality. Special attention is paid to wall shear stress (WSS), a factor known for its ability to produce atherosclerosis and bulges.… More >

Biyue Liu^1,*, Dalin Tang²

Molecular & Cellular Biomechanics, Vol.16, Suppl.2, pp. 25-26, 2019, DOI:10.32604/mcb.2019.06825

Abstract The blood flow and mass transport pattern of low-density lipoprotein (LDL) in a right coronary artery with two stenoses are studied. Computations were carried out under physiological conditions. Our results show a strong correlation between wall shear stress (WSS) and distribution patterns of LDL. More >

Yahui Zhang¹, Hui Wang^1,2, Zhouming Mai^1,2, Jianhang Du^1,2,3,*, Guifu Wu^1,2,3

Molecular & Cellular Biomechanics, Vol.16, Suppl.1, pp. 85-86, 2019, DOI:10.32604/mcb.2019.05836

Abstract Enhanced external counter pulsation (EECP) is an effective therapy to provide beneficial assistance for the failing heart by reducing cardiac afterload and increasing blood flow perfusion noninvasively. The technique of EECP involves the use of the EECP device to inflate and deflate a series of compression cuffs wrapped around the patient’s calves, lower thighs, and upper thighs. As the result, the enhanced flow perfusion is derived from the device’s propelling blood from veins of lower body to arteries of upper body and increases the blood supply for the important organs and brain. In the ACCF/AHA Guideline and ESC Guideline on… More >

Alvaro Valencia¹

Molecular & Cellular Biomechanics, Vol.1, No.3, pp. 221-232, 2004, DOI:10.3970/mcb.2004.001.221

Abstract Flow dynamics play an important role in the pathogenesis and treatment of intracranial aneurysms. The evaluation of the velocity field in the aneurysm dome and neck is important for the correct placement of endovascular coils, and the temporal and spatial variations of wall shear stress in the aneurysm are correlated with its growth and rupture. This numerical investigation describes the hemodynamic in two models of terminal aneurysm of the basilar artery. Aneurysm models with a aspect ratio of 1.0 and 1.67 were studied. Each model was subject to physiological representative waveform of inflow for a mean Reynolds number of 560.… More >

M. Thiriet¹, S. Naili², C. Ribreau²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 473-488, 2003, DOI:10.3970/cmes.2003.004.473

Abstract The laminar steady flow of incompressible Newtonian fluid is studied in rigid pipes with cross configuration of a collapsed tube to determine both the entry length and the wall shear stress (WSS). The cross section shapes have been defined from the collapse of an infinitely long elastic tube subjected to an uniform transmural pressure. Five characteristic collapsed configurations, from the unstressed down to the point-contact states, with a finite and infinite curvature radius at the contact point, are investigated, although the wall contact is not necessary observed in veins. Such collapsed shapes induce cross gradient in WSS in straight pipes.… More >

B. Liu¹, D. Tang²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.2, pp. 55-60, 2011, DOI:10.3970/icces.2011.017.055

Abstract The effects of the non-Newtonian blood viscosity on the wall shear stress (WSS) of the blood flows in stenotic right coronary arteries have been investigated by computer simulations. The numerical calculations were performed using the Newtonian Model and the non-Newtonian models with the fluid obeying the Power Law and the Carreau models for the simulations of unsteady blood flows. The differences on the spatial and temporal WSS distribution patterns due to the different blood properties were compared. The computational results demonstrate that the blood viscosity properties do not affect the spatial WSS distribution pattern qualitatively. The region on the inner… More >

Yang Li¹, Xiuxian Liu², Zhiyong Li^2,*, Jiayi Tong¹, Yi Feng¹, Genshan Ma¹, Chengxing Shen³, Naifeng Liu¹

Molecular & Cellular Biomechanics, Vol.14, No.4, pp. 213-229, 2017, DOI:10.3970/mcb.2017.014.213

Abstract Coronary tortuosity is a common angiographic finding, but the hemodynamic significance of coronary tortuosity is largely unknown. The impact of coronary tortuosity on coronary pressure and wall shear stress is still unclear. We addressed this issue in the present experimental study. A distorted tube model connected to heart pumping machine was established to simulate the coronary circulation. The pressure of each point was measured with a coronary pressure guidewire. Influence of tortuosity angle and tortuosity number on local pressure was measured. Wall shear stress was calculated accordingly to the pressure of each point. Pressure distribution in this system was affected… More >