A two-dimensional numerical study of peristaltic contractions in obstructed ureter flows

Najafi, Zahra; Schwartz, Bradley F.; Chandy, Abhilash J.; Mahajan, Anupama

doi:10.1080/10255842.2017.1415333

Cited by 11 publications

(12 citation statements)

References 25 publications

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“…By employing this realistic ureter model, they were able to investigate and analyze various aspects related to the urine movement through the ureter. Najafi et al [34,37] conducted experiments using both two-dimensional and three-dimensional ureter models to investigate the impact of obstruction on flow behaviour. They examined conditions with clogged and passable obstructions in order to study the factors that affect the flow dynamics within the ureter.…”

Section: Introductionmentioning

confidence: 99%

CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter

Keni,

Satish Shenoy,

Chethan

et al. 2024

Biomed. Phys. Eng. Express

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Ureters are essential components of the urinary system and play a crucial role in the transportation of urine from the kidneys to the bladder. In the current study, a three-dimensional ureter is modelled. A series of peristaltic waves are made to travel on the ureter wall to analyze and measure parameter effects such as pressure, velocity, gradient pressure, and wall shear at different time steps. The flow dynamics in the ureters are thoroughly analyzed using the commercially available ANSYS-CFX software. The maximum pressure is found in the triple wave at the ureteropelvic junction and maximum velocity is observed in the single and double wave motion due to the contraction produced by the peristalsis motion. The pressure gradient is maximum at the inlet of the ureter during the single bolus motion. The contraction produced a high jet of velocity due to neck formation and also helps in urine trapping in the form of a bolus, which leads to the formation of reverse flow. Due to the reduction in area, shear stress builds on the ureter wall. The high shear stress may rupture the junctions in the ureter.

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Section: Introductionmentioning

confidence: 99%

CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter

Keni,

Satish Shenoy,

Chethan

et al. 2024

Biomed. Phys. Eng. Express

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“…Most of the studies are carried on the normal constant diameter ureter. [11][12][13][14][15][16][17] Only a few numerical analysis is done on the variable diameter ureter. Srivastava et al, [18][19][20] studied the effect of viscosity variation on the peristalsis in the nonuniform tubes and channels.…”

Section: Introductionmentioning

confidence: 99%

“…Majority of the studies focus on flow dynamics in the ureter using a constant diameter ureter. Najafi et al [23,24] used the models of 2D and 3D obstructed constant diameter ureter. They studied the backflow, tapping, and reflux phenomenon in the ureter.…”

Section: Introductionmentioning

confidence: 99%

“…They demonstrated that urine reflux to the kidney happens as a result of the wave start and that as the wave moves to the outlet, the reflux at UPJ (ureteropelvic junction) decreases. The researchers [18][19][20][21][22] considered the peristalsis activity on the tapered organ and researchers [23][24][25][26][27][28][29][30] adopted the constant diameter ureter to understand the ureterdynamics during peristalsis [31] With the advancement in computational techniques, finite element analysis is used widely in medical applications. [32,33] The functioning of human organs can be studied using finite elment method (FEM), which indeed does not require any intervention during the primary investigation.…”

Section: Introductionmentioning

confidence: 99%

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Ureterdynamic Analysis of Multiple Peristaltic Waves on Variable Diameter Ureter

Keni¹,

Hayoz²,

Shenoy³

et al. 2022

Eng. Sci.

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In ureter physiology, the peristaltic mechanism is involved in urine transport from the kidney to the bladder through the ureter. The constrictions in the ureter develop the critical regions for ureter disease. ANSYS-CFX is used to analyze the flow dynamics. Multiple peristalsis waves are made to propagate over the tapered ureter model to understand the formation of bolus and reflux effect. The effect of the peristaltic sinusoidal wave propagating along the tapered circular tube results in pressure, velocity, pressure gradient, and wall shear distribution inside the ureter. The maximum pressure is created by the urine bolus of the single wave as it flows in front of the ascending urine bolus. This creates a negative pressure gradient, which can lead to a reverse flow. The high wall shear stress may affect the function of the kidney and play an important role in various kidney diseases. In triple wave due to incomplete wave propagation at the end, the minimum pressure gradient is recorded at the neck region due to contraction in the area. Also, the velocity shows a reverse flow at the outlet and this may lead to some urinary infection in the ureter.

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“…Najafi conducted a 2D axisymmetric numerical simulation of ureter peristalsis with different shapes and sizes of stones. Later, Najafi et al conducted numerical simulations of ureteral peristalsis with and without stones, and in these studies, only the fluid domain was considered and peristalsis was described as a series of sinusoidal waves.…”

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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A two-dimensional numerical study of peristaltic contractions in obstructed ureter flows

Cited by 11 publications

References 25 publications

CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter

CFD investigation of multiple peristaltic waves in a 3D unobstructed ureter

Ureterdynamic Analysis of Multiple Peristaltic Waves on Variable Diameter Ureter

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

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