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Partial Differential Equations - Modelling and ... - ResearchGate

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62 E.J. Dean <strong>and</strong> R. Glowinski<br />

Assuming that Ω is simply connected, we introduce:<br />

u = {u 1 ,u 2 } = {∂ψ/∂x 2 , −∂ψ/∂x 1 },<br />

v = {v 1 ,v 2 } = {∂ϕ/∂x 2 , −∂ϕ/∂x 1 },<br />

ω = ∂u 2 /∂x 1 − ∂u 1 /∂x 2 ,<br />

θ = ∂v 2 /∂x 1 − ∂v 1 /∂x 2 ,<br />

V g = {v | v ∈ (H 1 (Ω)) 2 , ∇ · v =0, v · n = dg/ds on Γ },<br />

V 0 = {v | v ∈ (H 1 (Ω)) 2 , ∇ · v =0, v · n =0onΓ },<br />

( )<br />

0 1<br />

L = .<br />

−1 0<br />

Above, n is the unit vector of the outward normal at Γ <strong>and</strong> s is a counterclockwise<br />

curvilinear abscissa on Γ . The formulation (71) is equivalent to<br />

⎧<br />

∫<br />

Find u(t) ∈ V g for<br />

∫<br />

all t>0 such that<br />

∫<br />

⎪⎨<br />

∂ω/∂t θ dx + ∇u:∇v dx = Lp : ∇v dx, ∀v ∈ V 0 ,<br />

Ω<br />

Ω<br />

Ω<br />

(72)<br />

∂p/∂t + p + ∂I Qf (p)+L∇u =0,<br />

⎪⎩<br />

{u(0), p(0),ω(0)} = {u 0 , p 0 ,ω 0 }.<br />

The problem (72) has a visco-elasticity flavor, −Lp playing here the role<br />

of the so-called extra-stress tensor. Ast → +∞, we obtain thus at the limit a<br />

(kind of) viscosity solution.<br />

Acknowledgement. The authors would like to thank J. D. Benamou, Y. Brenier,<br />

L. A. Caffarelli <strong>and</strong> P.-L. Lions for assistance <strong>and</strong> helpful comments <strong>and</strong> suggestions.<br />

The support of NSF (grant DMS-0412267) is also acknowledged.<br />

References<br />

[Aub82] Th. Aubin. Nonlinear Analysis on Manifolds, Monge–Ampère <strong>Equations</strong>.<br />

Springer-Verlag, Berlin, 1982.<br />

[Aub98] Th. Aubin. Some Nonlinear Problems in Riemanian Geometry. Springer-<br />

Verlag, Berlin, 1998.<br />

[BB00] J.-D. Benamou <strong>and</strong> Y. Brenier. A computational fluid mechanics solution<br />

to the Monge–Kantorovich mass transfer problem. Numer. Math.,<br />

84(3):375–393, 2000.<br />

[Cab02] X. Cabré. Topics in regularity <strong>and</strong> qualitative properties of solutions of<br />

nonlinear elliptic equations. Discrete Contin. Dyn. Syst., 8(2):331–359,<br />

2002.<br />

[CC95] L. A. Caffarelli <strong>and</strong> X. Cabré. Fully Nonlinear Elliptic <strong>Equations</strong>.<br />

American Mathematical Society, Providence, RI, 1995.<br />

[CH89] R. Courant <strong>and</strong> D. Hilbert. Methods of Mathematical Physics, Vol. II.<br />

Wiley Interscience, New York, 1989.

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