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Download full text - ELSA - Europa

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Shock tube (6)<br />

• Influence of pseudoviscosity q’<br />

and upwinding:<br />

p.v. pressure in optimal Eulerian sol.<br />

pressure<br />

l: characteristic length, a: wave speed<br />

Lagrangian solution needs some p.v.<br />

to be stable<br />

pressure<br />

pseudoviscous pressure<br />

Eulerian solution needs some<br />

upwinding to be stable<br />

α<br />

pressure<br />

0<br />

= β0 = 1<br />

α<br />

0<br />

= β0 = 0<br />

39<br />

Exercise 2 – Explosion in<br />

air-filled rigid tank<br />

This is a purely fluid problem because the tank is rigid and therefore<br />

does not need to be modeled. There is only one type of fluid (singlephase,<br />

single-component). This considerably simplifies the modeling,<br />

since the bubble surface may be treated as ALE.<br />

• Try out Lagrangian solution<br />

• Try out Eulerian solution<br />

• Try out ALE solution<br />

Gas<br />

(H-P)<br />

Gas<br />

(L-P)<br />

• …<br />

40<br />

20

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