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Dispersion and dissipation error in high-order Runge-Kutta ...

Dispersion and dissipation error in high-order Runge-Kutta ...

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∆ t / ∆ t max<br />

∆ t / ∆ t max<br />

1<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

−0.003<br />

−0.004<br />

−0.002<br />

DoF / λ<br />

10 9 8 7<br />

−0.003<br />

−0.004<br />

−0.006<br />

−0.006<br />

−0.01<br />

−0.008<br />

−0.01<br />

−0.008<br />

0.4<br />

0.4<br />

4 3.5 3<br />

λ / h<br />

(a) p = 1<br />

DoF / λ<br />

1<br />

15<br />

10<br />

5<br />

1<br />

0.8<br />

0.6<br />

−3e−07<br />

−1e−06<br />

−1e−06<br />

−3e−06<br />

−0.002<br />

−3e−06<br />

−1e−05<br />

−0.003<br />

−1e−05<br />

−0.004<br />

−0.0001<br />

−0.001<br />

−0.006<br />

1<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.8<br />

0.6<br />

∆ t / ∆ t ∆ t / ∆ t max<br />

max<br />

∆ t / ∆ t max<br />

∆ t / ∆ t max<br />

1<br />

0.8<br />

0.6<br />

−3e−05<br />

0.4<br />

0.2<br />

1<br />

0.8<br />

0.6<br />

14 12<br />

−0.0001<br />

−3e−05<br />

−0.0001<br />

−0.0003<br />

DoF / λ<br />

10 8<br />

−0.0003<br />

−0.001<br />

−0.001<br />

−0.01<br />

−0.01<br />

4 3.5 3 2.5 2 1.5<br />

λ / h<br />

(b) p = 2<br />

DoF / λ<br />

20 15 10<br />

−1e−08<br />

−1e−07<br />

−1e−08<br />

−1e−07<br />

6<br />

−1e−06<br />

−1e−05<br />

−0.0001<br />

−0.03<br />

−0.01<br />

4<br />

1<br />

−0.03<br />

−0.0001<br />

−0.001<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

1<br />

5<br />

1<br />

−0.001<br />

0.8<br />

0.6<br />

∆ t / ∆ t ∆ t / ∆ t max<br />

max<br />

0.4<br />

0.2<br />

−3e−07<br />

4<br />

3.5<br />

3<br />

2.5<br />

λ / h<br />

−0.0001<br />

2<br />

−0.001<br />

1.5 1<br />

0.4<br />

0.2<br />

0.4<br />

−1e−09<br />

0.2<br />

4<br />

3.5<br />

3<br />

−1e−06<br />

−1e−05<br />

2.5 2 1.5<br />

λ / h<br />

1<br />

0.4<br />

0.2<br />

(c) p = 3<br />

(d) p = 4<br />

∆ t / ∆ t max<br />

1<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.4<br />

0.3<br />

−1e−10<br />

3.5<br />

20<br />

−1e−09<br />

−1e−09<br />

3<br />

−1e−08<br />

DoF / λ<br />

15<br />

−1e−08<br />

−1e−07<br />

−1e−07<br />

−1e−06<br />

−1e−06<br />

10<br />

−1e−05<br />

−0.0001<br />

−1e−05<br />

−0.0001<br />

1<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.4<br />

0.3<br />

2.5 2 1.5 1<br />

λ / h<br />

∆ t / ∆ t max<br />

∆ t / ∆ t max<br />

DoF / λ<br />

10<br />

1<br />

9 8 7 6 5<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.4<br />

−1e−06<br />

−3e−07<br />

−1e−06<br />

1.2<br />

−3e−06<br />

−1e−05<br />

−3e−06<br />

1<br />

−1e−05<br />

−3e−05<br />

−0.0001<br />

−3e−05<br />

−0.0001<br />

0.8<br />

λ / h<br />

−0.001<br />

−0.001<br />

0.6<br />

4<br />

1<br />

0.9<br />

−0.01<br />

−0.01<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.4<br />

∆ t / ∆ t max<br />

(e) p = 5<br />

(f) p = 6<br />

Figure 6: Dissipation <strong>error</strong> as a function of wave length per mesh size (λ/h), degrees of<br />

freedom per wavelength (DoF/λ) <strong>and</strong> relative time step (∆t/∆t max ) for polynomial <strong>order</strong>s<br />

p = 1, 2, 3, 4, 5, 6 on a uniform mesh<br />

26

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