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Numerical Methods Contents - SAM

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Z<br />

Heat conduction: find temperature u = u(x, t)<br />

∂<br />

∂t u(x, t) − div(A(x)grad u(x, t)) = 0 in Ω × [0, T] , u(·, t) = g(t) on ∂Ω ,<br />

u(·, 0) = u 0 in Ω .<br />

X<br />

Z<br />

Y<br />

­1<br />

➍<br />

Viscous fluid flow problems<br />

­0.5<br />

0<br />

✁ Adaptive FEM for diffusion problem:<br />

Geometrically graded mesh at re-entrant corner<br />

(<strong>SAM</strong>, D-MATH, ETH Zürich)<br />

Stokes equations:<br />

0.5<br />

−∆u + gradp = f in Ω ,<br />

divu = 0 inΩ ,<br />

u = 0 on ∂Ω .<br />

1<br />

1<br />

0.5<br />

X<br />

0<br />

­0.5<br />

­1<br />

­1<br />

­0.5<br />

0<br />

Y<br />

0.5<br />

1<br />

✁ Vortex ring in flow at Re = 7500, (P. Koumoutsakos,<br />

D-INFK, ETH Zürich)<br />

➐<br />

Multilevel preconditioning<br />

➎<br />

Conservation laws<br />

Ôº½ ½¿º<br />

Ôº¿ ½¿º<br />

1<br />

1D scalar conservation law with flux f:<br />

∂<br />

∂t u(x,t) + ∂x ∂ (f(u)) = 0 in R × R+ ,<br />

u(x, 0) = u 0 (x) for x ∈ R .<br />

Inviscid fluid flow in 3D (<strong>SAM</strong>, D-MATH, ETH<br />

Zürich)<br />

✄<br />

FEM, FD, FV<br />

Huge sparse systems of equations<br />

Efficient preconditioners required<br />

1D hierarchical basis<br />

✄<br />

0.5<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

t<br />

2<br />

1<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

t<br />

2<br />

1<br />

➏<br />

Adaptive finite element methods<br />

0<br />

0 0.2 0.4 0.6 0.8 1<br />

t<br />

In SS10: Classes: Wed 8-10, HG E 3 and Fri 10-12, HG E 5<br />

Tutorials: Tue 13-15 HG E 21, Thu 13-15 HG D 7.2, Fri 15-17 G E 21<br />

Ôº¾ ½¿º<br />

Course: Parallel Computing for Scientific Simulations<br />

Ôº ½¿º

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