An Automated Method for Extracting Spatially Varying Time-Dependent Quantities from an ALEGRA Simulation Using VisIt Visualization Software

2014 ◽  
Author(s):  
Matthew J. Coppinger
Author(s):  
Adel Hamdi ◽  
Imed Mahfoudhi

AbstractThe paper deals with the nonlinear inverse source problem of identifying an unknown time-dependent point source occurring in a two-dimensional evolution advection-dispersion-reaction equation with spatially varying velocity field and dispersion tensor. The


1993 ◽  
Vol 3 (1) ◽  
pp. 421-424 ◽  
Author(s):  
E.A. Scholle ◽  
J. Schwartz

Author(s):  
Ian Jordaan

Ice mechanical behavior is time-dependent, as has been known for many decades. But in many references, the attempt is made to use time-independent plasticity theory. The relevant analytical approach that accounts for time is viscoelastic theory. The need for this approach is made quite essential by study of microstructural changes that occur in ice under high stresses. In no case does there appear to be a clear yield condition, with flow occurring after a certain threshold value. Furthermore, the microstructural changes occurring under stress result in a highly significant enhancement of the creep rates. This results in a spatially varying viscoelastic response that is a function of prior stress history. The ice response is then a function of position resulting in a microstucturally modified layer in the region where compressive stress is applied. This can be deep or highly localized, depending on the loading rate. The most promising approach is that based on damage mechanics combined with viscoelasticity, using the thermodynamics of irreversible processes. Ice is also prone to fracture, especially at high loading rates and under high stresses. This is basic to the notion of scale effect. Fracture processes are also time-dependent in viscoelastic materials, a phenomenon that needs to be explored further. Furthermore, failure often will take place in a random fashion, depending on the distribution of flaws in ice. This indicates strongly that a theory based on “weakest-link” hypotheses and probability theory is appropriate. Finally, some aspects relevant to practical data analysis are discussed. These include measurement uncertainties of Molikpaq data, and geometric approximations of ice features, e.g. ridges as uniform beams.


1964 ◽  
Vol 7 (8) ◽  
pp. 1385 ◽  
Author(s):  
D. J. Benney ◽  
S. Rosenblat

Author(s):  
G. Richard Christie ◽  
Poul M.F. Nielsen ◽  
Shane A. Blackett ◽  
Chris P. Bradley ◽  
Peter J. Hunter

The field modelling language FieldML is being developed as a standard for modelling and interchanging field descriptions in software, suitable for a wide range of computation techniques. It comprises a rich set of operators for defining generalized fields as functions of other fields, starting with basic domain fields including sets of discrete objects and coordinate systems. It is extensible by adding new operators and by their arbitrary combination in expressions, making it well suited for describing the inherent complexity of biological materials and organ systems. This paper describes the concepts behind FieldML, including a simple example of a spatially varying finite-element field. It outlines current implementations in established, open source computation and visualization software, both drawing on decades of bioengineering modelling software development experience.


1994 ◽  
Vol 116 (3) ◽  
pp. 499-507 ◽  
Author(s):  
J. S. Nigen ◽  
C. H. Amon

Convective heat transport in a grooved channel is numerically investigated using a time-dependent formulation. Conjugate conduction/convection and uniform heat-flux representations for the solid domain are considered. For the conjugate representation, the solid domain is composed of multiple materials and concentrated heat generation. The associated cooling flows include laminar and transitional regimes. Steady and time-dependent contours of the streamfunction and local skin-friction coefficients are presented. Additionally, local distributions of Nusselt number and surface temperature are displayed for both the conjugate and convection-only representations. These results are contrasted over the range of Reynolds numbers explored to demonstrate the significance of including time-dependency and conjugation in the study of convective heat transport. Such considerations are found to be important in the design and analysis of heat exchanger configurations with spatially varying material composition and concentrated heat generation.


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