scholarly journals Computational Fluid Dynamics Support for Fontan Planning in Minutes, Not Hours: The Next Step in Clinical Pre-Interventional Simulations

2021 ◽  
Author(s):  
Petter Frieberg ◽  
Nicolas Aristokleous ◽  
Pia Sjöberg ◽  
Johannes Töger ◽  
Petru Liuba ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computation Time ◽  
Left Pulmonary Artery ◽  
Cfd Modeling ◽  
Resonance Imaging ◽  
Computational Fluid Dynamics Cfd ◽  
Magnetic Resonance Imaging Mri ◽  
Cfd Method ◽  
Fontan Patients

AbstractComputational fluid dynamics (CFD) modeling may aid in planning of invasive interventions in Fontan patients. Clinical application of current CFD techniques is however limited by complexity and long computation times. Therefore, we validated a “lean” CFD method to magnetic resonance imaging (MRI) and an “established” CFD method, ultimately aiming to reduce complexity to enable predictive CFD during ongoing interventions. Fifteen Fontan patients underwent MRI for CFD modeling. The differences between lean and established approach, in hepatic and total flow percentage to the left pulmonary artery (%LPA), power loss and relative wall shear stress area were 1.5 ± 4.0%, -0.17 ± 1.1%, -0.055 ± 0.092 mW and 1.1 ± 1.4%. Compared with MRI, the lean and established method showed a bias in %LPA of -1.9 ± 3.4% and -1.8 ± 3.1%. Computation time was for the lean and established approach 3.0 ± 2.0 min and 7.0 ± 3.4 h, respectively. We conclude that the proposed lean method provides fast and reliable results for future CFD support during interventions. Graphical abstract

A Longitudinal Study of Hemodynamics in a Functional Human Hemodialysis Fistula Using 3T Magnetic Resonance Imaging-Based Computational Fluid Dynamics Analysis

2010 ◽  
Author(s):  
Yong He ◽  
Christi M. Terry ◽  
Scott A. Berceli ◽  
Alfred K. Cheung ◽  
Yan-Ting E. Shiu
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Magnetic Resonance Imaging Mri ◽  
Stage Renal Disease ◽  
End Stage

An arteriovenous fistula (AVF) is the preferred vascular access for hemodialysis in end-stage renal disease. However, 60% of AVFs fail to achieve sufficient lumen dilation to allow adequate blood flow for chronic dialysis [1]. Although hemodynamics is likely an important modulator of AVF maturation and remodeling, the AVF hemodynamic spatial distribution profiles and their relationship with AVF maturation and remodeling are unclear [2]. Based on data collected from magnetic resonance imaging (MRI) of an AVF and computational fluid dynamics (CFD) simulations, we developed a protocol for longitudinal (over time) and noninvasive monitoring of geometry and hemodynamics of human AVF.

scholarly journals Validasi Model Turbulensi pada Simulasi Numerik Menggunakan Software Fluent dengan Sayap Onera M6

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Sulistiya Sulistiya ◽  
Alief Sadlie Kasman
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Result ◽  
Computational Simulation ◽  
Turbulence Models ◽  
Wind Tunnels ◽  
Direct Testing ◽  
The World ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

AbstractNumerical simulation using Computational Fluid Dynamics (CFD) method is one way of predicting airflow characteristics on the model. This method is widely used because it is relatively inexpensive and faster in getting desired results compared with performing direct testing. The correctness of a computational simulation output is highly dependent on the input and how it was processed. In this paper, simulation is done on Onera M6 Wing, to investigate the effect of a turbulence model’s application on the accuracy of the computational result. The choice of Onera M6 Wing as a simulation’s model is due to its extensive database of testing results from various wind tunnels in the world. Among Turbulence models used are Spalart-Allmaras, K-Epsilon, K-Omega, and SST.Keywords: CFD, fluent, Model, Turbulence, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.AbstraksSimulasi numerik dengan menggunakan metode Computational Fluid Dynamics (CFD) merupakan salah satu cara untuk memprediksi karakteristik suatu aliran udara yang terjadi pada model. Metode ini banyak digunakan karena sifatnya yang relatif murah dan cepat untuk mendapatkan hasil dibandingkan dengan melakukan pengujian langsung. Benar tidak hasil sebuah simulasi komputasi sangat tergantung pada inputan yang diberikan serta cara memproses data inputan tersebut. Pada tulisan ini dilakukan simulasi dengan menggunakan sayap onera M6 dengan tujuan untuk mengetahui pengaruh penggunaan model turbulensi terhadap keakuratan hasil komputasi. Pilihan sayap onera M6 sebagai model simulasi dikarenakan model tersebut sudah memiliki database hasil pengujian yang cukup lengkap dan sudah divalidasi dari berbagai terowongan angin di dunia. Model turbulensi yang digunakan diantaranya Spalart-Allmaras, K-Epsilon, K-Omega dan SST.Kata Kunci : CFD, fluent, Model, Turbulensi, Onera M6, Spalart-Allmaras, K-Epsilon, K-Omega, SST.

scholarly journals THE COMBUSTION ENGINE INTAKE MANIFOLD CFD MODELING DEPENDING ON THE AIRBOX CONFIGURATION

2021 ◽  
Vol 2021 (6) ◽  
pp. 5421-5425
Author(s):  
MICHAL RICHTAR ◽  
◽  
PETRA MUCKOVA ◽  
JAN FAMFULIK ◽  
JAKUB SMIRAUS ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Stationary Flow ◽  
Cfd Modeling ◽  
Intake Manifold ◽  
Combustion Engines ◽  
Computational Fluid Dynamics Cfd

The aim of the article is to present the possibilities of application of computational fluid dynamics (CFD) to modelling of air flow in combustion engine intake manifold depending on airbox configuration. The non-stationary flow occurs in internal combustion engines. This is a specific type of flow characterized by the fact that the variables depend not only on the position but also on the time. The intake manifold dimension and geometry strongly effects intake air amount. The basic target goal is to investigate how the intake trumpet position in the airbox impacts the filling of the combustion chamber. Furthermore, the effect of different distances between the trumpet neck and the airbox wall in this paper will be compared.

An Assessment of Computational Fluid Dynamics Cavitation Models Using Bubble Growth Theory and Bubble Transport Modeling

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Michael P. Kinzel ◽  
Jules W. Lindau ◽  
Robert F. Kunz
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Analytic Solutions ◽  
Cfd Modeling ◽  
Computational Time ◽  
Cavitation Model ◽  
Modeling Framework ◽  
Homogeneous Models ◽  
Bubble Transport ◽  
Computational Fluid Dynamics Cfd

This effort investigates advancing cavitation modeling relevant to computational fluid dynamics (CFD) through two strategies. The first aims to reformulate the cavitation models and the second explores adding liquid–vapor slippage effects. The first aspect of the paper revisits cavitation model formulations with respect to the Rayleigh–Plesset equation (RPE). The present approach reformulates the cavitation model using analytic solutions to the RPE. The benefit of this reformulation is displayed by maintaining model sensitivities similar to RPE, whereas the standard models fail these tests. In addition, the model approach is extended beyond standard homogeneous models, to a two-fluid modeling framework that explicitly models the slippage between cavitation bubbles and the liquid. The results indicate a significant impact of slip on the predicted cavitation solution, suggesting that the inclusion of such modeling can potentially improve CFD cavitation models. Overall, the results of this effort point to various aspects that may be considered in future CFD-modeling efforts with the goal of improving the model accuracy and reducing computational time.

scholarly journals Biomagnetic Monitoring vs. CFD Modeling: A Real Case Study of Near-Source Depositions of Traffic-Related Particulate Matter along a Motorway

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1285
Author(s):  
Sarah Letaïef ◽  
Pierre Camps ◽  
Thierry Poidras ◽  
Patrick Nicol ◽  
Delphine Bosch ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particulate Matter ◽  
Cfd Simulation ◽  
Low Cost ◽  
Precast Concrete ◽  
Cfd Modeling ◽  
Concrete Wall ◽  
Fluorescence Measurements ◽  
Computational Fluid Dynamics Cfd

A test site located along a 12-lane motorway east of Montpellier, France, is used to evaluate the potential of biomagnetic monitoring on traffic-related particulate matter (PM) to parametrize a computational fluid dynamics (CFD) simulation of the local airflow. Two configurations were established on the site with three vegetated flat-top earth berms of a basic design, and a fourth one was located windward to the traffic roofed with a 4-m-high precast concrete wall. As a first step, PM deposition simultaneously on plant leaves, on low-cost passive artificial filters, and on soils was estimated from proxies supplied by magnetic and X-ray fluorescence measurements on both sides of the motorway. These latter revealed that traffic-related pollutants are present on soils samples highlighted with a clear fingerprint of combustion residues, and wears of breaks, vehicles, and highway equipment. Maximum PM accumulations were detected in the lee of the berm–wall combination, while no significant deposition was observed on both sides of the flat-top earth berms. These results are in line with measurements from PM µ-sensors operated by the regional state-approved air quality agency. Finally, we compared the experimental measurements with the outcomes of a computational fluid dynamics (CFD) modeling based on the Reynolds-Averaged Navier–Stokes (RANS) equations that consider the traffic-induced momentum and turbulence. The CFD modeling matches the experimental results by predicting a recirculated flow in the near wake of the berm–wall combination that enhances the PM concentration, whereas the flat-top berm geometry does not alter the pollutants’ transport and indeed contributes to their atmospheric dispersion.

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