Computational fluid dynamics with stents: quantitative comparison with particle image velocimetry for three commercial off the shelf intracranial stents

Background and purposeValidation of computational fluid dynamics (CFD) in stented intracranial aneurysms (IAs) is still lacking, to reliably predict prone to occlusion hemodynamics, probing, in particular, velocity reduction, and flow pattern changes. This study compares CFD outcome with particle imaging velocimetry (PIV) for three commercial off the shelf (COTS) stents of different material densities.Material and methodsThe recently developed uniform and high precision multi-time lag PIV method was applied to a sidewall aneurysm before and after implantation of three COTS stents with high, intermediate, and low material densities. The measured laser sheet flow patterns and velocity reductions were compared with CFD results and correlated with stent material density.ResultsVelocity reduction was in good agreement for unstented high and low porosity stented IA, while flow pattern change was fully matched for unstented and high porosity stented IA. Poor CFD–PIV matching in IA was found for intermediate porosity stents.ConclusionsCFD reproduced fully PIV measurements in unstented and high porosity stented IAs. With low porosity stents, CFD reproduced velocity reduction and high velocities close to the neck, while a marked mismatch on sluggish flow was found at the dome. CFD was unable to match PIV with intermediate porosity stents for which hemodynamic transition occurred.

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The Aerodynamics of a Diabolo

10.31224/osf.io/azmxu ◽

2021 ◽

Author(s):

Darren Jia

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Angular Momentum ◽

Flow Pattern ◽

High Spin ◽

Angular Speed ◽

Geometric Shape ◽

Cfd Simulations ◽

Resistive Torque ◽

Computational Fluid Dynamics Cfd

Diabolo is a popular game in which the object can be spun at up to speeds of 5000 rpm. This high spin velocity gives the diabolo the necessary angular momentum to remain stable. The shape of the diabolo generates an interesting air flow pattern. The viscous air applies a resistive torque on the fast spinning diabolo. Through computational fluid dynamics (CFD) simulations it's shown that the resistive torque has an interesting dependence on the angular speed of the diabolo. Further, the geometric shape of the diabolo affects the dependence of torque on angular speed.

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Experimental and CFD Modelling: Impact of the Inlet Slug Flow on the Horizontal Gas–Liquid Separator

Energies ◽

10.3390/en12010041 ◽

2018 ◽

Vol 12 (1) ◽

pp. 41

Author(s):

Siong Lee ◽

Thomas Choong ◽

Luqman Abdullah ◽

Mus’ab Abdul Razak ◽

Zhen Ban

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Liquid Phase ◽

Flow Pattern ◽

Slug Flow ◽

Cavity Formation ◽

Cfd Modelling ◽

Computational Fluid Dynamics Cfd ◽

The Impact ◽

Liquid Separator

For a gas-liquid separator sizing, many engineers have neglected the flow pattern of incoming fluids. The impact of inlet slug flow which impeded onto the separator’s liquid phase will cause a separator fails to perform when sloshing happened in the separator. To date, the study on verifying the impact of inlet slug flow in a separator remains limited. In this paper, the impact of inlet momentum and inlet slug flow on the hydrodynamics in a separator for cases without an inlet device were investigated. The experimental and Computational Fluid Dynamics (CFD) results of cavity formation and sloshing occurrence in the separator in this study were compared. A User Defined Function (UDF) was used to describe the inlet slug flow at the separator inlet. Inlet slug flow occurred at inlet momentum from 200 to 1000 Pa, and sloshing occurred in the separator at 1000 Pa. Both experimental and simulated results showed similar phenomena.

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Multi-Cell Concept for Simulating Fires in Big Enclosures Using a Zone Model

Journal of Fire Sciences ◽

10.1177/073490419601400302 ◽

1996 ◽

Vol 14 (3) ◽

pp. 186-198 ◽

Cited By ~ 14

Author(s):

W.K. Chow

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Temperature Distribution ◽

Physical Properties ◽

Flow Pattern ◽

Layer Thickness ◽

Zone Model ◽

Smoke Layer

The multi-cell concept is applied to simulate fire in a big com partment with the zone model CFAST. The predicted physical properties of the smoke layer are used to justify the results, including the smoke layer tempera ture, smoke layer thickness and flows between each cell. Microscopic pictures of the flow pattern and smoke temperature distribution similar to the results pre dicted by the Computational Fluid Dynamics technique can be obtained. This idea is recommended to study fires in big enclosures.

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Manufacturing and Computational Fluid Dynamics Modeling of a Patient-Specific Fistula Model

Volume 4: Bio and Sustainable Manufacturing ◽

10.1115/msec2017-3002 ◽

2017 ◽

Author(s):

Yang Liu ◽

Yihao Zheng ◽

John Pitre ◽

William Weitzel ◽

Joseph Bull ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Patient Specific ◽

Cfd Model ◽

Dynamics Modeling ◽

Computational Fluid Dynamics Modeling ◽

Computational Fluid Dynamics Cfd ◽

Particle Imaging ◽

Venous Wall ◽

Good Agreement

Arteriovenous fistula is the joining of an artery to a vein to create vascular access for dialysis. The failure or maturation of fistula is affected by the vessel wall shear stress (WSS), which is difficult to measure in clinic. A computational fluid dynamics (CFD) model was built to estimate WSS of a patient-specific fistula model. To validate this model, a silicone phantom was manufactured and used to carry out a particle imaging velocimetry (PIV) experiment. The flow field from the PIV experiment shows a good agreement with the CFD model. From the CFD model, the highest WSS (40 Pa) happens near the anastomosis. WSS in the vein is larger than that in the artery. WSS on the outer venous wall is larger than that on the inner wall. The combined technique of additive manufacturing, silicone molding, and CFD is an effective tool to understand the maturation mechanism of a fistula.

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Application of Computational Fluid Dynamics to Closed-Loop Bioreactors: I. Characterization and Simulation of Fluid-Flow Pattern and Oxygen Transfer

Water Environment Research ◽

10.2175/106143006x136739 ◽

2007 ◽

Vol 79 (6) ◽

pp. 600-612 ◽

Cited By ~ 20

Author(s):

Helen X. Littleton ◽

Glen T. Daigger ◽

Peter F. Strom

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Fluid Flow ◽

Flow Pattern ◽

Oxygen Transfer ◽

Closed Loop

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Hydroacoustic Sonification and Flow Pattern Investigation of Venous Pulsatile Tinnitus Using MEMS Hydrophone Sensing and Dye Flow Visualization Techniques: Pilot 3D Printing, Computational Fluid Dynamics, and Psychoacoustic Study

Sensors and Materials ◽

10.18494/sam.2021.3519 ◽

2021 ◽

Vol 33 (10) ◽

pp. 3439

Author(s):

Yue-Lin Hsieh ◽

Xing Wang ◽

Xiaobing Xu ◽

Yongzhen Wu ◽

Shenjiang Wang ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

3D Printing ◽

Flow Visualization ◽

Flow Pattern ◽

Pulsatile Tinnitus ◽

Visualization Techniques

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Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room With Rounded Edges

Volume 11: Emerging Technologies ◽

10.1115/imece2013-65843 ◽

2013 ◽

Author(s):

A. Idris ◽

B. P. Huynh

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Speed ◽

Flow Pattern ◽

Flow Rate ◽

Software Package ◽

Computational Study ◽

Ventilation Rate ◽

3 Dimensional ◽

Computational Fluid Dynamics Cfd

A commercial Computational Fluid Dynamics (CFD) software package is used to investigate numerically a 3-dimensional rectangular-box room with rounded edges. The room has all its window openings located on one wall only. The standard K-ε turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. Especially, comparison with ventilation rate corresponding to when the room edges are sharp is made; and thereby the effects of the edges being rounded are examined.

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The Effects of the Presence of a Kitchen House on the Wind Flow Surrounding a Low-Rise Building

Energies ◽

10.3390/en13236243 ◽

2020 ◽

Vol 13 (23) ◽

pp. 6243

Author(s):

Siti Noratikah Che Deraman ◽

Saddam Hussein Abo Sabah ◽

Shaharudin Shah Zaini ◽

Taksiah A. Majid ◽

Amin Al-Fakih

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Pattern ◽

Air Flow ◽

Flow Characteristics ◽

Wind Flow ◽

Cfd Simulations ◽

The Core ◽

Computational Fluid Dynamics Cfd ◽

Gap Height

Most Malaysian rural houses are categorized as non-engineered buildings and vulnerable to damage during events such as windstorms due to the fact that these houses lack engineering considerations. These houses are characterized by having an attached kitchen house, and many of these houses were previously damaged by thunderstorms. The current research investigated the air flow characteristics changes surrounding these houses as a result of the presence of the kitchen. The roof pitch, position, gap height, and overhang were investigated using computational fluid dynamics (CFD) simulations. The results showed that the kitchen position at the center resulted in a slight increase in the suction on the ridge of the roof; however, it significantly altered the flow pattern in the windward and leeward directions. The results also showed that the roof overhang, roof pitch, and kitchen position contributed severely to the damage of the rural house. Moreover, the highest suction occurred at the roof ridge when the kitchen was located at the center of the rural house (Cp = −2.28). Therefore, the authors believe that it is more advantageous to have a kitchen connected to the core as it reduces the pressure on the roof of the core during thunderstorm events.

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Optimization design of submerged propeller in oxidation ditch by computational fluid dynamics and comparison with experiments

Water Science & Technology ◽

10.2166/wst.2016.184 ◽

2016 ◽

Vol 74 (3) ◽

pp. 681-690 ◽

Cited By ~ 5

Author(s):

Yuquan Zhang ◽

Yuan Zheng ◽

E. Fernandez-Rodriguez ◽

Chunxia Yang ◽

Yantao Zhu ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Energy Consumption ◽

Flow Field ◽

Flow Pattern ◽

Operating Conditions ◽

Oxidation Ditch ◽

Actual Measurement ◽

Operating Condition ◽

Rotating Speed

The operating condition of a submerged propeller has a significant impact on flow field and energy consumption of the oxidation ditch. An experimentally validated numerical model, based on the computational fluid dynamics (CFD) tool, is presented to optimize the operating condition by considering two important factors: flow field and energy consumption. Performance demonstration and comparison of different operating conditions were carried out in a Carrousel oxidation ditch at the Yingtang wastewater treatment plants in Anhui Province, China. By adjusting the position and rotating speed together with the number of submerged propellers, problems of sludge deposit and the low velocity in the bend could be solved in a most cost-effective way. The simulated results were acceptable compared with the experimental data and the following results were obtained. The CFD model characterized flow pattern and energy consumption in the full-scale oxidation ditch. The predicted flow field values were within −1.28 ± 7.14% difference from the measured values. By determining three sets of propellers under the rotating speed of 6.50 rad/s with one located 5 m from the first curved wall, after numerical simulation and actual measurement, not only the least power density but also the requirement of the flow pattern could be realized.

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