Simulation of the Upper Urinary System

Hosseini, Ghazaleh; Williams, John; Avital, Eldad; Munjiza, Ante; Xu, Dong; Green, James S. A.

doi:10.1615/critrevbiomedeng.2013009704

Cited by 15 publications

(16 citation statements)

References 28 publications

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“…The projection method was used to decouple flow velocities and pressure. The capability of CgLes to simulate both laminar and turbulent flow has been extensively verified [17–19]. An implicit Crank-Nicolson scheme for the time-stepping was used for the diffusion term.…”

Section: Methodsmentioning

confidence: 99%

An Investigation on the Aggregation and Rheodynamics of Human Red Blood Cells Using High Performance Computations

Avital

et al. 2017

Scientifica

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Studies on the haemodynamics of human circulation are clinically and scientifically important. In order to investigate the effect of deformation and aggregation of red blood cells (RBCs) in blood flow, a computational technique has been developed by coupling the interaction between the fluid and the deformable RBCs. Parallelization was carried out for the coupled code and a high speedup was achieved based on a spatial decomposition. In order to verify the code's capability of simulating RBC deformation and transport, simulations were carried out for a spherical capsule in a microchannel and multiple RBC transport in a Poiseuille flow. RBC transport in a confined tube was also carried out to simulate the peristaltic effects of microvessels. Relatively large-scale simulations were carried out of the motion of 49,512 RBCs in shear flows, which yielded a hematocrit of 45%. The large-scale feature of the simulation has enabled a macroscale verification and investigation of the overall characteristics of RBC aggregations to be carried out. The results are in excellent agreement with experimental studies and, more specifically, both the experimental and simulation results show uniform RBC distributions under high shear rates (60–100/s) whereas large aggregations were observed under a lower shear rate of 10/s.

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Section: Methodsmentioning

confidence: 99%

An Investigation on the Aggregation and Rheodynamics of Human Red Blood Cells Using High Performance Computations

Avital

et al. 2017

Scientifica

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“…In Equations (4)- (9), u c is the combined standard uncertainty, C x is the sensitivity coefficient for each variable, and u(x) is the standard uncertainty for each variable.…”

Section: Circulation Setupmentioning

confidence: 99%

“…CFD can conveniently describe the occurrence of ureteral obstructions. 8,9 In addition, many studies have investigated urinary flow in the ureter in relation to peristalsis. 10,11 Clavica et al 12 developed an artificial model of the ureter to obtain information about what may induce critical pressure.…”

Section: Introductionmentioning

confidence: 99%

Urine flow analysis using double J stents of various sizes in in vitro ureter models

Kim

Choi

et al. 2020

Numer Methods Biomed Eng

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A double J stent (DJS) is used to alleviate the congestion of urine in the upper urinary tract when there is ureteral stenosis, which causes the interruption of normal urine flow and results in renal failure. The purpose of placing DJSs is to ensure sufficient urine flow in the ureter, but the DJS acts as a foreign body in the urinary system and sometimes acts as an obstacle in achieving sufficient urine flow. Here, to evaluate the performance of various sizes of DJSs, 5Fr (1.666 mm) to 8Fr (2.666 mm), in the ureter, silicon ureter models without stenosis, and a circulation setup were constructed. The total flow rates (TFRs) in the stented ureters were evaluated with an in vitro experiment. The TFRs in the 5Fr DJS were larger than those in the other sizes of DJS. As the size of DJS increased, the TFR decreased. Computational fluid dynamics was also applied to validate the experimental results. It was shown that the experimental results agreed well with the numerical results.

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“…A numerical study that incorporates a two‐way fully coupled fluid‐structure interaction (FSI) is imperative. Hosseini et al conducted 3D numerical studies where they coupled a CFD code with a discrete model element approach . Ureter wall mechanical properties were assumed to be linear, elastic, and homogeneous.…”

Section: Introductionmentioning

confidence: 99%

A fluid‐structure interaction (FSI)‐based numerical investigation of peristalsis in an obstructed human ureter

Takaddus

Gautam

Chandy

2018

Numer Methods Biomed Eng

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Urine moves from the kidney to the bladder through the ureter. A series of compression waves facilitates this transport. Due to the highly concentrated mineral deposits in urine, stones are formed in the kidney and travel down through the urinary tract. While passing, a larger stone can get stuck and cause severe damage to ureter wall. Also, stones in the ureter obstructing the urine flow can cause pain and backflow of urine which in turn might require surgical intervention. The current study develops a 2D axisymmetric numerical model to gain an understanding of the ureter obstruction and its effects on the flow, which are critical in assessing the different treatment options. Transient computational analysis involving a two-way fully coupled fluid-structure interaction with the arbitrary Lagrangian-Eulerian method between the ureteral wall and urine flow is conducted with an obstruction in the ureter. The ureter wall is modeled as an anisotropic hyperelastic material, data of which, is based on biaxial tests on human ureter from previous literature, while the incompressible Navier-Stokes equations are solved to calculate urine flow. A finite element-based monolithic solver is used for the simulations here. The obstruction is placed in the fluid domain as a circular stone at the proximal part of the ureter. One of the objectives of this study is to quantify the effect of the ureteral obstruction. A sharp jump in pressure gradient and wall shear stress, as well as retrograde urine flow, is observed as a result of the obstruction.

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Simulation of the Upper Urinary System

Cited by 15 publications

References 28 publications

An Investigation on the Aggregation and Rheodynamics of Human Red Blood Cells Using High Performance Computations

An Investigation on the Aggregation and Rheodynamics of Human Red Blood Cells Using High Performance Computations

Urine flow analysis using double J stents of various sizes in in vitro ureter models

A fluid‐structure interaction (FSI)‐based numerical investigation of peristalsis in an obstructed human ureter

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