The role of computational fluid dynamics (CFD) in aircraft design

1990 ◽  
Author(s):  
EDWARD TINOCO
Author(s):  
Charlotte Debbaut ◽  
Jan Vierendeels ◽  
Denis Van Loo ◽  
Christophe Casteleyn ◽  
Pieter Cornillie ◽  
...  

The perfusion of the liver is complex, especially at the microcirculatory level. The functional units of the liver are often schematized as hexagonal lobules (Fig. 1a), which receive blood from the peripheral portal triads (PT; including hepatic arterioles and portal venules). A part of the PT blood drains into the vascular septa (VS), which are the vascular beds delineating the lobule boundaries in between successive portal triads. Subsequently, the blood enters the interconnected network of tortuous sinusoids, where the metabolic exchange with neighboring hepatocytes takes place. Afterwards, blood drains radially into the central vein. Despite this well-known conceptual model, liver microcirculation is still not fully understood. Previously, the liver microhemodynamics have been modeled using simplified (2D) geometries and/or a porous media approach with an isotropic permeability. However, the validity of these assumptions has never been assessed. Therefore, the aim of this study was threefold. First, the (an)isotropic permeability behavior of an image-based 3D sinusoidal network was quantified using computational fluid dynamics (CFD). Secondly, the resulting permeability tensor was applied to build a 3D CFD porous medium model of a liver lobule. Thirdly, the role of VS in hepatic microperfusion was investigated by comparing a porous lobule model with and without VS.


2009 ◽  
Vol 2009 ◽  
pp. 1-12 ◽  
Author(s):  
Pankaj K. Singh ◽  
Alberto Marzo ◽  
Stuart C. Coley ◽  
Guntram Berti ◽  
Philippe Bijlenga ◽  
...  

Objective. The importance of hemodynamics in the etiopathogenesis of intracranial aneurysms (IAs) is widely accepted. Computational fluid dynamics (CFD) is being used increasingly for hemodynamic predictions. However, alogn with the continuing development and validation of these tools, it is imperative to collect the opinion of the clinicians.Methods. A workshop on CFD was conducted during the European Society of Minimally Invasive Neurological Therapy (ESMINT) Teaching Course, Lisbon, Portugal. 36 delegates, mostly clinicians, performed supervised CFD analysis for an IA, using the @neuFuse software developed within the European project @neurIST. Feedback on the workshop was collected and analyzed. The performance was assessed on a scale of 1 to 4 and, compared with experts' performance.Results. Current dilemmas in the management of unruptured IAs remained the most important motivating factor to attend the workshop and majority of participants showed interest in participating in a multicentric trial. The participants achieved an average score of 2.52 (range 0–4) which was 63% (range 0–100%) of an expert user.Conclusions. Although participants showed a manifest interest in CFD, there was a clear lack of awareness concerning the role of hemodynamics in the etiopathogenesis of IAs and the use of CFD in this context. More efforts therefore are required to enhance understanding of the clinicians in the subject.


1996 ◽  
Vol 33 (9) ◽  
pp. 163-170 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul

Research was undertaken in order to identify possible methodologies for the prediction of sedimentation in storage chambers based on computational fluid dynamics (CFD). The Fluent CFD software was used to establish a numerical model of the flow field, on which further analysis was undertaken. Sedimentation was estimated from the simulated flow fields by two different methods. The first approach used the simulation to predict the bed shear stress distribution, with deposition being assumed for areas where the bed shear stress fell below a critical value (τcd). The value of τcd had previously been determined in the laboratory. Efficiency was then calculated as a function of the proportion of the chamber bed for which deposition had been predicted. The second method used the particle tracking facility in Fluent and efficiency was calculated from the proportion of particles that remained within the chamber. The results from the two techniques for efficiency are compared to data collected in a laboratory chamber. Three further simulations were then undertaken in order to investigate the influence of length to breadth ratio on chamber performance. The methodology presented here could be applied to complex geometries and full scale installations.


2021 ◽  
Vol 54 ◽  
pp. 102207
Author(s):  
Cristian Inostroza ◽  
Alessandro Solimeno ◽  
Joan García ◽  
José M. Fernández-Sevilla ◽  
F. Gabriel Acién

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