Preface to the special issue “Recent progress in numerical methods for nonlinear time-dependent flow & transport problems”

2018 ◽  
Vol 169 ◽  
pp. 1-2 ◽  
Author(s):  
Michael Dumbser ◽  
Vladimir Titarev ◽  
Richard Saurel
Keyword(s):  
Numerical Methods ◽  
Recent Progress ◽  
Time Dependent ◽  
Special Issue ◽  
Flow Transport ◽  
Dependent Flow ◽  
Transport Problems

Flow Mixing Enhancement from Balloon Pulsations in an Intravenous Oxygenator

2004 ◽  
Vol 127 (3) ◽  
pp. 400-415 ◽  
Author(s):  
Amador M. Guzmán ◽  
Rodrigo A. Escobar ◽  
Cristina H. Amon
Keyword(s):  
Numerical Simulations ◽  
Oxygen Transfer ◽  
Fiber Bundle ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Three Dimensional ◽  
Time Dependent ◽  
Fiber Placement ◽  
Flow Mixing ◽  
Dependent Flow

Computational investigations of flow mixing and oxygen transfer characteristics in an intravenous membrane oxygenator (IMO) are performed by direct numerical simulations of the conservation of mass, momentum, and species equations. Three-dimensional computational models are developed to investigate flow-mixing and oxygen-transfer characteristics for stationary and pulsating balloons, using the spectral element method. For a stationary balloon, the effect of the fiber placement within the fiber bundle and the number of fiber rings is investigated. In a pulsating balloon, the flow mixing characteristics are determined and the oxygen transfer rate is evaluated. For a stationary balloon, numerical simulations show two well-defined flow patterns that depend on the region of the IMO device. Successive increases of the Reynolds number raise the longitudinal velocity without creating secondary flow. This characteristic is not affected by staggered or non-staggered fiber placement within the fiber bundle. For a pulsating balloon, the flow mixing is enhanced by generating a three-dimensional time-dependent flow characterized by oscillatory radial, pulsatile longitudinal, and both oscillatory and random tangential velocities. This three-dimensional flow increases the flow mixing due to an active time-dependent secondary flow, particularly around the fibers. Analytical models show the fiber bundle placement effect on the pressure gradient and flow pattern. The oxygen transport from the fiber surface to the mean flow is due to a dominant radial diffusion mechanism, for the stationary balloon. The oxygen transfer rate reaches an asymptotic behavior at relatively low Reynolds numbers. For a pulsating balloon, the time-dependent oxygen-concentration field resembles the oscillatory and wavy nature of the time-dependent flow. Sherwood number evaluations demonstrate that balloon pulsations enhance the oxygen transfer rate, even for smaller flow rates.

Special Issue dedicated to Numerical Methods for Viscosity Solutions and Applications

2013 ◽  
Vol 73 ◽  
pp. 1
Author(s):  
Maurizio Falcone ◽  
Roberto Ferretti ◽  
Ian M. Mitchell ◽  
Hongkai Zhao
Keyword(s):  
Numerical Methods ◽  
Viscosity Solutions ◽  
Special Issue

Visualization of Parameter Sensitivity of 2D Time-Dependent Flow

2018 ◽  
pp. 359-370
Author(s):  
Karsten Hanser ◽  
Ole Klein ◽  
Bastian Rieck ◽  
Bettina Wiebe ◽  
Tobias Selz ◽  
...  
Keyword(s):  
Parameter Sensitivity ◽  
Time Dependent ◽  
Dependent Flow
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