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Full-Text Articles in Engineering
Aortic Coarctation: Recent Developments In Experimental And Computational Methods To Assess Treatments For This Simple Condition, John F. Ladisa, Charles A. Taylor, Jeffrey A. Feinstein
Aortic Coarctation: Recent Developments In Experimental And Computational Methods To Assess Treatments For This Simple Condition, John F. Ladisa, Charles A. Taylor, Jeffrey A. Feinstein
Biomedical Engineering Faculty Research and Publications
Coarctation of the aorta (CoA) is often considered a relatively simple disease, but long-term outcomes suggest otherwise as life expectancies are decades less than in the average population and substantial morbidity often exists. What follows is an expanded version of collective work conducted by the authors' and numerous collaborators that was presented at the 1st International Conference on Computational Simulation in Congenital Heart Disease pertaining to recent advances for CoA. The work begins by focusing on what is known about blood flow, pressure and indices of wall shear stress (WSS) in patients with normal vascular anatomy from both clinical imaging …
Local Hemodynamic Changes Caused By Main Branch Stent Implantation And Subsequent Side Branch Balloon Angioplasty In A Representative Coronary Bifurcation, Andrew R. Williams, Bon-Kwon Koo, Timothy J. Gundert, Peter J. Fitzgerald, John F. Ladisa Jr.
Local Hemodynamic Changes Caused By Main Branch Stent Implantation And Subsequent Side Branch Balloon Angioplasty In A Representative Coronary Bifurcation, Andrew R. Williams, Bon-Kwon Koo, Timothy J. Gundert, Peter J. Fitzgerald, John F. Ladisa Jr.
Biomedical Engineering Faculty Research and Publications
Abnormal blood flow patterns promoting inflammation, cellular proliferation, and thrombosis may be established by local changes in vessel geometry after stent implantation in bifurcation lesions. Our objective was to quantify altered hemodynamics due to main vessel (MV) stenting and subsequent virtual side branch (SB) angioplasty in a coronary bifurcation by using computational fluid dynamics (CFD) analysis. CFD models were generated from representative vascular dimensions and intravascular ultrasound images. Time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and fractional flow reserve (FFR) were quantified. None of the luminal surface was exposed to low TAWSS (/cm2) in the nondiseased bifurcation model. …
Uncertainty Quantification Integrated To The Cfd Modeling Of Synthetic Jet Actuators, Srikanth Adya, Daoru Frank Han, Serhat Hosder
Uncertainty Quantification Integrated To The Cfd Modeling Of Synthetic Jet Actuators, Srikanth Adya, Daoru Frank Han, Serhat Hosder
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Point Collocation Non-Intrusive Polynomial Chaos (NIPC) method has been applied to two stochastic synthetic jet actuator problems used as test cases in the CFDVAL2004 workshop to demonstrate the integration of computationally efficient uncertainty quantification to the high-fidelity CFD modeling of synthetic jet actuators. In Case1 where the synthetic jet is issued into quiescent air, the NIPC method is used to quantify the uncertainty in the long-time averaged u and v-velocities at several locations in the flow field, due to the uniformly distributed uncertainty introduced in the amplitude and frequency of the oscillation of the piezo-electric membrane. Fifth order NIPC …
Viscosity Effects In Vibratory Mobilization Of Residual Oil, Igor A. Beresnev, Wen Deng
Viscosity Effects In Vibratory Mobilization Of Residual Oil, Igor A. Beresnev, Wen Deng
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The last decade has seen clarifications of the underlying capillary physics behind stimulation of oil production by seismic waves and vibrations. Computational studies have prevailed, however, and no viscous hydrodynamic theory of the phenomenon has been proposed. For a body of oil entrapped in a pore channel, viscosity effects are naturally incorporated through a model of two-phase core-annular flow. These effects are significant at the postmobilization stage, when the resistance of capillary forces is overcome and viscosity becomes the only force resisting an oil ganglion's motion. A viscous equation of motion follows, and computational fluid dynamics (CFD) establishes the limits …
Numerical Modeling And Experimental Investigation Of Gas-Liquid Slug Formation In A Microchannel T-Junction, Rafael M. Santos, Masahiro Kawaji
Numerical Modeling And Experimental Investigation Of Gas-Liquid Slug Formation In A Microchannel T-Junction, Rafael M. Santos, Masahiro Kawaji
Faculty Publications and Scholarship
Gas-liquid two-phase flow in a microfluidic T-junction with nearly square microchannels of 113 μm hydraulic diameter was investigated experimentally and numerically. Air and water superficial velocities were 0.018–0.791 m/s and 0.042–0.757 m/s, respectively. Three-dimensional modeling was performed with computational fluid dynamics (CFD) software FLUENT and the volume-of-fluid (VOF) model. Slug flow (snapping/breaking/jetting) and stratified flow were observed experimentally. Numerically predicted void fraction followed a linear relationship with the homogeneous void fraction, while experimental values depended on the superficial velocity ratio UG/UL. Higher experimental velocity slip caused by gas inlet pressure build-up and oscillation caused deviation from numerical predictions. Velocity slip …
Predicting Neointimal Hyperplasia In Stented Arteries Using Time-Dependant Computational Fluid Dynamics: A Review, Jonathan Murphy, Fergal Boyle
Predicting Neointimal Hyperplasia In Stented Arteries Using Time-Dependant Computational Fluid Dynamics: A Review, Jonathan Murphy, Fergal Boyle
Articles
This paper reviews the recent literature regarding the time-dependant computational fluid dynamics (CFD) analyses of blood flow through implanted coronary stents. The in vivo processes which result in arterial restenosis are identified. The definition and range of the computationally predicted variables which are believed to stimulate the restenosis processes are evaluated. The reviewed literature is subdivided into effect-based in which the effects of altering the flow model are investigated and design-based in which different geometric stent configurations are compared. Finally, conclusions are made regarding the body of work reviewed and recommendations are provided for future work in this field.