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Partial Differential Equations - Modelling and ... - ResearchGate

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22 V. Girault <strong>and</strong> M.F. Wheeler<br />

Y, meters<br />

600<br />

500<br />

400<br />

300<br />

200<br />

100<br />

Cone<br />

1.0E+02<br />

4.2E+03<br />

2.2E+04<br />

1.0E+03<br />

4.0E+04<br />

2.2E+04<br />

1.0E+04<br />

4.0E+05<br />

2.2E+05<br />

1.0E+05<br />

4.0E+05<br />

2.2E+05<br />

1.0E+05<br />

4.2E+07<br />

2.2E+07<br />

1.0E+07<br />

4.2E+06<br />

2.2E+06<br />

1.0E+06<br />

Y, meters<br />

600<br />

500<br />

400<br />

300<br />

200<br />

100<br />

0 0 5000 10000 15000<br />

X, meters<br />

20000 25000<br />

0 0 5000 10000 15000 20000 25000<br />

X, meters<br />

Fig. 4. Simulation of nuclear reactive transport using DG - 1<br />

600<br />

500<br />

Y, meters<br />

400<br />

300<br />

200<br />

100<br />

0<br />

0 5000 10000 15000 20000 25000<br />

X, meters<br />

Fig. 5. Simulation of nuclear reactive transport using DG - 2<br />

advection-dominated <strong>and</strong> diffusion-dominated problems. Figure 4 shows Iodine<br />

concentration at 200K years <strong>and</strong> Figure 5 at 2 million years. The low<br />

numerical diffusion of the DG method was also found to be important in<br />

this benchmark problem because of the long simulation time, cf. [WESR03].<br />

Details regarding this simulation <strong>and</strong> several mesh adaptation strategies are<br />

discussed in [SW06a, SW06b]. The latter demonstrated that by employing dynamic<br />

adaptivity, time-dependent transport could be resolved without slope<br />

limiting for both long-term <strong>and</strong> short-term simulations. Moreover, mass conservation<br />

was retained locally during dynamic mesh modification.<br />

The theoretical <strong>and</strong> computational results obtained for primal DG methods<br />

for transport <strong>and</strong> flow are summarized in Table 1. Two rows provide a<br />

comparison of the methods for treating flow problems with highly varying

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