A Parametric Geometry Computational Fluid Dynamics (CFD) Study Utilizing Design of Experiments (DOE)

Rhew, Ray D.; Parker, Peter A.

doi:10.2514/6.2007-1615

Cited by 7 publications

(6 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method is similar to the analysis technique presented by Rhew and Parker [29]. Following the 2 Â 2 Â 2 factorial analysis, two 2-factor two-level analyses were conducted to consider the effects of geometry on untreated and treated aneurysm hemodynamics separately.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

Nair

Chong

Indahlastari

et al. 2016

Journal of Biomechanical Engineering

View full text Add to dashboard Cite

Embolic coiling is one of the most effective treatments for cerebral aneurysms (CAs), largely due to the hemodynamic modifications that the treatment effects in the aneurysmal environment. However, coiling can have very different hemodynamic outcomes in aneurysms with different geometries. Previous work in the field of biofluid mechanics has demonstrated on a general level that geometry is a driving factor behind aneurysmal hemodynamics. The goal of this study was to relate two specific geometric factors that describe CAs (i.e., dome size (DS) and parent-vessel contact-angle (PV-CA)) and one factor that describes treatment (i.e., coil packing density (PD)) to three clinically relevant hemodynamic responses (i.e., aneurysmal root-mean-square velocity (Vrms), aneurysmal wall shear stress (WSS), and cross-neck flow (CNF)). Idealized models of basilar tip aneurysms were created in both virtual and physical forms to satisfy two-level multifactorial experimental designs. Steady and pulsatile flow hemodynamics were then evaluated in the virtual models using computational fluid dynamics (CFD) (before and after virtual treatment with finite element (FE) embolic coil models), and hemodynamics were also evaluated in the physical models using particle image velocimetry (PIV) (before and after treatment with actual embolic coils). Results showed that among the factors considered, PD made the greatest contributions to effects on hemodynamic responses in and around the aneurysmal sac (i.e., Vrms and WSS), while DS made the greatest contributions to effects on hemodynamics at the neck (i.e., CNF). Results also showed that while a geometric factor (e.g., PV-CA) may play a relatively minor role in dictating hemodynamics in the untreated case, the same factor can play a much greater role after coiling. We consider the significance of these findings in the context of aneurysmal recurrence and rupture, and explore potential roles for the proposed methods in endovascular treatment planning.

show abstract

Section: Discussionmentioning

confidence: 99%

Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

Nair

Chong

Indahlastari

et al. 2016

Journal of Biomechanical Engineering

View full text Add to dashboard Cite

show abstract

“…Contributions of the geometric factors (and their interactions) toward modifying hemodynamic responses were then calculated by dividing individual SS values by the total SS. More detail on related statistical analyses can be found in Rhew et al (Rhew and Parker, 2007). Hemodynamic responses were also compared directly between the ABTA models and their matching IBTA counterparts using Pearson correlation.…”

Section: Computational Data Analysismentioning

confidence: 99%

Hemodynamic characterization of geometric cerebral aneurysm templates

Nair

Chong

Indahlastari

et al. 2016

Journal of Biomechanics

View full text Add to dashboard Cite

Hemodynamics are currently considered to a lesser degree than geometry in clinical practices for evaluating cerebral aneurysm (CA) risk and planning CA treatment. This study establishes fundamental relationships between three clinically recognized CA geometric factors and four clinically relevant hemodynamic responses. The goal of the study is to develop a more combined geometric/hemodynamic basis for informing clinical decisions. Flows within eight idealized template geometries were simulated using computational fluid dynamics and measured using particle image velocimetry under both steady and pulsatile flow conditions. The geometric factor main effects were then analyzed to quantify contributions made by the geometric factors (aneurysmal dome size (DS), dome-to-neck ratio (DNR), and parent-vessel contact angle (PV-CA)) to effects on the hemodynamic responses (aneurysmal and neck-plane root-mean-square velocity magnitude (Vrms), aneurysmal wall shear stress (WSS), and cross-neck flow (CNF)). Two anatomical aneurysm models were also examined to investigate how well the idealized findings would translate to more realistic CA geometries. DNR made the greatest contributions to effects on hemodynamics including a 75.05% contribution to aneurysmal Vrms and greater than 35% contributions to all responses. DS made the next greatest contributions, including a 43.94% contribution to CNF and greater than 20% contributions to all responses. PV-CA and several factor interactions also made contributions of greater than 10%. The anatomical aneurysm models and the most similar idealized templates demonstrated consistent hemodynamic response patterns. This study demonstrates how individual geometric factors, and combinations thereof, influence CA hemodynamics. Bridging the gap between geometry and flow in this quantitative yet practical way may have potential to improve CA evaluation and treatment criteria. Agreement among results from idealized and anatomical models further supports the potential for a template-based approach to play a useful role in clinical practice.

show abstract

“…Despite the availability of high performance computing (HPC) facilities, the routine use of computational fluid dynamics (CFD) is yet restricted to a pre-defined (small) number of configurations. Two remarkable studies are those of Rogers et al (2003) at NASA Ames and of Rhew and Parker (2007) at NASA Langley. The reasons that linear methods have cornered the industrial aircraft design process are twofold.…”

Section: Introductionmentioning

confidence: 99%

Adaptive design of experiments for efficient and accurate estimation of aerodynamic loads

Ronch

Panzeri

Bari

et al. 2017

Aircraft Eng & Aerospace Tech

View full text Add to dashboard Cite

Aerodynamic design, which aims at developing the outer shape of the aircraft while meeting several contrasting requirements, demands an accurate and reliable aerodynamic database. Computing forces and moments with the highest level of delity is a prerequisite, but practically limited by wall clock time and available computing resources. An ecient and robust approach is therefore sought after. This study investigates two design of experiments algorithms in combination with surrogate modelling. In traditional design of experiments, the samples are selected a priori before running the numerical explorative campaign. It is wellknown that this may result in either poor prediction capabilities or high computational costs. The second strategy employs an adaptive design of experiments algorithm. As opposed to the former, this is a selflearning technique that iteratively: i) identies the regions of the design space that are characterised by stronger nonlinearities; * First corresponding author. Email: A.Da-Ronch@soton.ac.uk Preprint submitted to SCAD 2016 August 10, 2016 and ii) select the new samples in order to maximise the information content associated with the simulations to be performed during the next iteration. In this work, the Reynoldsaveraged NavierStokes equations are solved around a complete aircraft conguration. A representative ight envelope is created taking the angle of attack and Mach number as design parameters. The adaptive strategy is found to perform better than the traditional counterpart. This is quantied in terms of the sum of the squared error between the surrogate model predictions and CFD results. For the pitch moment coecient, which shows strong nonlinearities, the error metric using the adaptive strategy is reduced by about one order of magnitude compared to the traditional approach. Furthermore, the proposed adaptive methodology, which is employed on a high performance computing facility, requires no extra costs or complications than a traditional methodology.

show abstract

A Parametric Geometry Computational Fluid Dynamics (CFD) Study Utilizing Design of Experiments (DOE)

Cited by 7 publications

References 1 publication

Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

Hemodynamic characterization of geometric cerebral aneurysm templates

Adaptive design of experiments for efficient and accurate estimation of aerodynamic loads

Contact Info

Product

Resources

About