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A particle-in-Burgers model: theory and numerics - Laboratoire de ...

A particle-in-Burgers model: theory and numerics - Laboratoire de ...

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Mo<strong>de</strong>l <strong>and</strong> motivation Auxiliary steps Results h = 0: coupl<strong>in</strong>g h = 0: <strong>de</strong>f<strong>in</strong>ition, uniqueness h = 0: <strong>numerics</strong>, existence The coupled problem<br />

...Frozen <strong>particle</strong>: <strong>de</strong>f<strong>in</strong>ition(s)...<br />

Let us provi<strong>de</strong> alternative characterizations of entropy solutions:<br />

Proposition (equivalent <strong>de</strong>f<strong>in</strong>itions)<br />

A function u ∈ L ∞ (R + ×R) is an entropy solution if <strong>and</strong> only if it satisfies any<br />

of the follow<strong>in</strong>g assertions:<br />

A. The function u verifies the adapted entropy <strong>in</strong>equalities with<br />

(c−, c+) ∈ G 1 λ ∪ G 2 λ.<br />

B. The function u verifies the Kruzhkov entropy <strong>in</strong>equalities for all<br />

nonnegative test function ϕ ∈ C ∞ c (R + ×R) such that ϕ|x=0 = 0,<br />

moreover,<br />

for a. e. t > 0 ((γ−u)(t), (γ+u)(t)) ∈ Gλ.<br />

D. There exists C = C(λ,u∞, c±) such that the function u verifies<br />

∀ϕ ∈ C ∞ c (R + <br />

×R), ϕ 0<br />

R +<br />

<br />

[|u−c(x)|∂tϕ+Φ(u, c(x))∂xϕ] dx dt<br />

R<br />

<br />

+ |u0 − c(x)| ϕ(0, x) dx −C(ϕ)dist<br />

R<br />

(c−, c+), Gλ)<br />

for all (c−, c+) ∈ R×R.

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