Displaying similar documents to “Free convection flow of water at 4 C past an infinite porous plate with constant suction”

A second order unconditionally positive space-time residual distribution method for solving compressible flows on moving meshes

Dobeš, Jiří, Deconinck, Herman

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A space-time formulation for unsteady inviscid compressible flow computations in 2D moving geometries is presented. The governing equations in Arbitrary Lagrangian-Eulerian formulation (ALE) are discretized on two layers of space-time finite elements connecting levels n , n + 1 / 2 and n + 1 . The solution is approximated with linear variation in space (P1 triangle) combined with linear variation in time. The space-time residual from the lower layer of elements is distributed to the nodes at level...

An attraction result and an index theorem for continuous flows on n × [ 0 , )

Klaudiusz Wójcik (1997)

Annales Polonici Mathematici

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We study the behavior of a continuous flow near a boundary. We prove that if φ is a flow on E = n + 1 for which E = n × 0 is an invariant set and S ⊂ ∂E is an isolated invariant set, with non-zero homological Conley index, then there exists an x in EE such that either α(x) or ω(x) is in S. We also prove an index theorem for a flow on n × [ 0 , ) .

Monotonicity of first eigenvalues along the Yamabe flow

Liangdi Zhang (2021)

Czechoslovak Mathematical Journal

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We construct some nondecreasing quantities associated to the first eigenvalue of - Δ φ + c R ( c 1 2 ( n - 2 ) / ( n - 1 ) ) along the Yamabe flow, where Δ φ is the Witten-Laplacian operator with a C 2 function φ . We also prove a monotonic result on the first eigenvalue of - Δ φ + 1 4 ( n / ( n - 1 ) ) R along the Yamabe flow. Moreover, we establish some nondecreasing quantities for the first eigenvalue of - Δ φ + c R a with a ( 0 , 1 ) along the Yamabe flow.

Relaxation of the incompressible porous media equation

László Székelyhidi Jr (2012)

Annales scientifiques de l'École Normale Supérieure

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It was shown recently by Córdoba, Faraco and Gancedo in [1] that the 2D porous media equation admits weak solutions with compact support in time. The proof, based on the convex integration framework developed for the incompressible Euler equations in [4], uses ideas from the theory of laminates, in particular T 4 configurations. In this note we calculate the explicit relaxation of IPM, thus avoiding T 4 configurations. We then use this to construct weak solutions to the unstable interface...

Local-in-time existence for the non-resistive incompressible magneto-micropolar fluids

Peixin Zhang, Mingxuan Zhu (2022)

Applications of Mathematics

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We establish the local-in-time existence of a solution to the non-resistive magneto-micropolar fluids with the initial data u 0 H s - 1 + ε , w 0 H s - 1 and b 0 H s for s > 3 2 and any 0 < ε < 1 . The initial regularity of the micro-rotational velocity w is weaker than velocity of the fluid u .

Generalized gradient flow and singularities of the Riemannian distance function

Piermarco Cannarsa (2012-2013)

Séminaire Laurent Schwartz — EDP et applications

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Significant information about the topology of a bounded domain Ω of a Riemannian manifold M is encoded into the properties of the distance, d Ω , from the boundary of Ω . We discuss recent results showing the invariance of the singular set of the distance function with respect to the generalized gradient flow of d Ω , as well as applications to homotopy equivalence.

Ricci flow coupled with harmonic map flow

Reto Müller (2012)

Annales scientifiques de l'École Normale Supérieure

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We investigate a coupled system of the Ricci flow on a closed manifold M with the harmonic map flow of a map φ from M to some closed target manifold N , t g = - 2 Rc + 2 α φ φ , t φ = τ g φ , where α is a (possibly time-dependent) positive coupling constant. Surprisingly, the coupled system may be less singular than the Ricci flow or the harmonic map flow alone. In particular, we can always rule out energy concentration of  φ a-priori by choosing α large enough. Moreover, it suffices to bound the curvature...

Pairs of square-free values of the type n 2 + 1 , n 2 + 2

Stoyan Dimitrov (2021)

Czechoslovak Mathematical Journal

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We show that there exist infinitely many consecutive square-free numbers of the form n 2 + 1 , n 2 + 2 . We also establish an asymptotic formula for the number of such square-free pairs when n does not exceed given sufficiently large positive number.

Measure-preserving homeomorphisms of noncompact manifolds and mass flow toward ends

Tatsuhiko Yagasaki (2007)

Fundamenta Mathematicae

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Suppose M is a noncompact connected n-manifold and ω is a good Radon measure of M with ω(∂M) = 0. Let ℋ(M,ω) denote the group of ω-preserving homeomorphisms of M equipped with the compact-open topology, and E ( M , ω ) the subgroup consisting of all h ∈ ℋ(M,ω) which fix the ends of M. S. R. Alpern and V. S. Prasad introduced the topological vector space (M,ω) of end charges of M and the end charge homomorphism c ω : E ( M , ω ) ( M , ω ) , which measures for each h E ( M , ω ) the mass flow toward ends induced by h. We show that the...

Three examples of brownian flows on

Yves Le Jan, Olivier Raimond (2014)

Annales de l'I.H.P. Probabilités et statistiques

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We show that the only flow solving the stochastic differential equation (SDE) on d X t = 1 { X t g t ; 0 } W + ( d t ) + 1 { X t l t ; 0 } d W - ( d t ) , where W + and W - are two independent white noises, is a coalescing flow we will denote by ϕ ± . The flow ϕ ± is a Wiener solution of the SDE. Moreover, K + = 𝖤 [ δ ϕ ± | W + ] is the unique solution (it is also a Wiener solution) of the SDE K s , t + f ( x ) = f ( x ) + s t K s , u ( 1 + f ' ) ( x ) W + ( d u ) + 1 2 s t K s , u f ` ` ( x ) d u for s l t ; t , x and f a twice continuously differentiable function. A third flow ϕ + can be constructed out of the n -point motions of K + . This flow is coalescing and its n -point motion...

Consecutive square-free values of the type x 2 + y 2 + z 2 + k , x 2 + y 2 + z 2 + k + 1

Ya-Fang Feng (2023)

Czechoslovak Mathematical Journal

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We show that for any given integer k there exist infinitely many consecutive square-free numbers of the type x 2 + y 2 + z 2 + k , x 2 + y 2 + z 2 + k + 1 . We also establish an asymptotic formula for 1 x , y , z H such that x 2 + y 2 + z 2 + k , x 2 + y 2 + z 2 + k + 1 are square-free. The method we used in this paper is due to Tolev.

On uniqueness for bounded channel flows of viscoelastic fluids

Marshall J. Leitman, Epifanio G. Virga (1988)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti

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It was conjectured in [1] that there is at most one bounded channel flow for a viscoelastic fluid whose stress relaxation function G is positive, integrable, and strictly convex. In this paper we prove the uniqueness of bounded channel flows, assuming G to be non-negative, integrable, and convex, but different from a very specific piecewise linear function. Furthermore, whenever these hypotheses apply, the unbounded channel flows, if any, must grow in time faster than any polynomial. ...