Geometric Optics for Surface Waves in Nonlinear Elasticity

Geometric Optics for Surface Waves in Nonlinear Elasticity PDF Author: Jean-François Coulombel
Publisher: American Mathematical Soc.
ISBN: 1470440377
Category : Education
Languages : en
Pages : 164

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Book Description
This work is devoted to the analysis of high frequency solutions to the equations of nonlinear elasticity in a half-space. The authors consider surface waves (or more precisely, Rayleigh waves) arising in the general class of isotropic hyperelastic models, which includes in particular the Saint Venant-Kirchhoff system. Work has been done by a number of authors since the 1980s on the formulation and well-posedness of a nonlinear evolution equation whose (exact) solution gives the leading term of an approximate Rayleigh wave solution to the underlying elasticity equations. This evolution equation, which is referred to as “the amplitude equation”, is an integrodifferential equation of nonlocal Burgers type. The authors begin by reviewing and providing some extensions of the theory of the amplitude equation. The remainder of the paper is devoted to a rigorous proof in 2D that exact, highly oscillatory, Rayleigh wave solutions uε to the nonlinear elasticity equations exist on a fixed time interval independent of the wavelength ε, and that the approximate Rayleigh wave solution provided by the analysis of the amplitude equation is indeed close in a precise sense to uε on a time interval independent of ε. This paper focuses mainly on the case of Rayleigh waves that are pulses, which have profiles with continuous Fourier spectrum, but the authors' method applies equally well to the case of wavetrains, whose Fourier spectrum is discrete.

Geometric Optics for Surface Waves in Nonlinear Elasticity

Geometric Optics for Surface Waves in Nonlinear Elasticity PDF Author: Jean-François Coulombel
Publisher: American Mathematical Soc.
ISBN: 1470440377
Category : Education
Languages : en
Pages : 164

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Book Description
This work is devoted to the analysis of high frequency solutions to the equations of nonlinear elasticity in a half-space. The authors consider surface waves (or more precisely, Rayleigh waves) arising in the general class of isotropic hyperelastic models, which includes in particular the Saint Venant-Kirchhoff system. Work has been done by a number of authors since the 1980s on the formulation and well-posedness of a nonlinear evolution equation whose (exact) solution gives the leading term of an approximate Rayleigh wave solution to the underlying elasticity equations. This evolution equation, which is referred to as “the amplitude equation”, is an integrodifferential equation of nonlocal Burgers type. The authors begin by reviewing and providing some extensions of the theory of the amplitude equation. The remainder of the paper is devoted to a rigorous proof in 2D that exact, highly oscillatory, Rayleigh wave solutions uε to the nonlinear elasticity equations exist on a fixed time interval independent of the wavelength ε, and that the approximate Rayleigh wave solution provided by the analysis of the amplitude equation is indeed close in a precise sense to uε on a time interval independent of ε. This paper focuses mainly on the case of Rayleigh waves that are pulses, which have profiles with continuous Fourier spectrum, but the authors' method applies equally well to the case of wavetrains, whose Fourier spectrum is discrete.

Shocks, Singularities and Oscillations in Nonlinear Optics and Fluid Mechanics

Shocks, Singularities and Oscillations in Nonlinear Optics and Fluid Mechanics PDF Author: Ferruccio Colombini
Publisher: Springer
ISBN: 3319520423
Category : Mathematics
Languages : en
Pages : 313

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Book Description
The book collects the most relevant results from the INdAM Workshop "Shocks, Singularities and Oscillations in Nonlinear Optics and Fluid Mechanics" held in Rome, September 14-18, 2015. The contributions discuss recent major advances in the study of nonlinear hyperbolic systems, addressing general theoretical issues such as symmetrizability, singularities, low regularity or dispersive perturbations. It also investigates several physical phenomena where such systems are relevant, such as nonlinear optics, shock theory (stability, relaxation) and fluid mechanics (boundary layers, water waves, Euler equations, geophysical flows, etc.). It is a valuable resource for researchers in these fields.

Localization for $THH(ku)$ and the Topological Hochschild and Cyclic Homology of Waldhausen Categories

Localization for $THH(ku)$ and the Topological Hochschild and Cyclic Homology of Waldhausen Categories PDF Author: Andrew J. Blumberg
Publisher: American Mathematical Soc.
ISBN: 1470441780
Category : Mathematics
Languages : en
Pages : 112

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Book Description
The authors resolve the longstanding confusion about localization sequences in $THH$ and $TC$ and establish a specialized devissage theorem.

Affine Flag Varieties and Quantum Symmetric Pairs

Affine Flag Varieties and Quantum Symmetric Pairs PDF Author: Zhaobing Fan
Publisher: American Mathematical Soc.
ISBN: 1470441756
Category : Mathematics
Languages : en
Pages : 136

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Book Description
The quantum groups of finite and affine type $A$ admit geometric realizations in terms of partial flag varieties of finite and affine type $A$. Recently, the quantum group associated to partial flag varieties of finite type $B/C$ is shown to be a coideal subalgebra of the quantum group of finite type $A$.

Degree Theory of Immersed Hypersurfaces

Degree Theory of Immersed Hypersurfaces PDF Author: Harold Rosenberg
Publisher: American Mathematical Soc.
ISBN: 1470441853
Category : Mathematics
Languages : en
Pages : 74

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Book Description
The authors develop a degree theory for compact immersed hypersurfaces of prescribed $K$-curvature immersed in a compact, orientable Riemannian manifold, where $K$ is any elliptic curvature function.

Minimal Weak Truth Table Degrees and Computably Enumerable Turing Degrees

Minimal Weak Truth Table Degrees and Computably Enumerable Turing Degrees PDF Author: Rodney G. Downey
Publisher: American Mathematical Soc.
ISBN: 1470441624
Category : Mathematics
Languages : en
Pages : 104

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Book Description
First, there are sets with minimal weak truth table degree which bound noncomputable computably enumerable sets under Turing reducibility. Second, no set with computable enumerable Turing degree can have minimal weak truth table degree. Third, no $Delta^0_2$ set which Turing bounds a promptly simple set can have minimal weak truth table degree.

Conformal Graph Directed Markov Systems on Carnot Groups

Conformal Graph Directed Markov Systems on Carnot Groups PDF Author: Vasileios Chousionis
Publisher: American Mathematical Soc.
ISBN: 1470442159
Category : Mathematics
Languages : en
Pages : 170

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Book Description
The authors develop a comprehensive theory of conformal graph directed Markov systems in the non-Riemannian setting of Carnot groups equipped with a sub-Riemannian metric. In particular, they develop the thermodynamic formalism and show that, under natural hypotheses, the limit set of an Carnot conformal GDMS has Hausdorff dimension given by Bowen's parameter. They illustrate their results for a variety of examples of both linear and nonlinear iterated function systems and graph directed Markov systems in such sub-Riemannian spaces. These include the Heisenberg continued fractions introduced by Lukyanenko and Vandehey as well as Kleinian and Schottky groups associated to the non-real classical rank one hyperbolic spaces.

Global Smooth Solutions for the Inviscid SQG Equation

Global Smooth Solutions for the Inviscid SQG Equation PDF Author: Angel Castro
Publisher: American Mathematical Soc.
ISBN: 1470442140
Category : Mathematics
Languages : en
Pages : 102

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Book Description
In this paper, the authors show the existence of the first non trivial family of classical global solutions of the inviscid surface quasi-geostrophic equation.

Explicit Arithmetic of Jacobians of Generalized Legendre Curves Over Global Function Fields

Explicit Arithmetic of Jacobians of Generalized Legendre Curves Over Global Function Fields PDF Author: Lisa Berger
Publisher: American Mathematical Soc.
ISBN: 1470442191
Category : Mathematics
Languages : en
Pages : 144

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Book Description
The authors study the Jacobian $J$ of the smooth projective curve $C$ of genus $r-1$ with affine model $y^r = x^r-1(x + 1)(x + t)$ over the function field $mathbb F_p(t)$, when $p$ is prime and $rge 2$ is an integer prime to $p$. When $q$ is a power of $p$ and $d$ is a positive integer, the authors compute the $L$-function of $J$ over $mathbb F_q(t^1/d)$ and show that the Birch and Swinnerton-Dyer conjecture holds for $J$ over $mathbb F_q(t^1/d)$.

Dynamics Near the Subcritical Transition of the 3D Couette Flow I: Below Threshold Case

Dynamics Near the Subcritical Transition of the 3D Couette Flow I: Below Threshold Case PDF Author: Jacob Bedrossian
Publisher: American Mathematical Soc.
ISBN: 1470442175
Category : Mathematics
Languages : en
Pages : 170

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Book Description
The authors study small disturbances to the periodic, plane Couette flow in the 3D incompressible Navier-Stokes equations at high Reynolds number Re. They prove that for sufficiently regular initial data of size $epsilon leq c_0mathbf {Re}^-1$ for some universal $c_0 > 0$, the solution is global, remains within $O(c_0)$ of the Couette flow in $L^2$, and returns to the Couette flow as $t rightarrow infty $. For times $t gtrsim mathbf {Re}^1/3$, the streamwise dependence is damped by a mixing-enhanced dissipation effect and the solution is rapidly attracted to the class of ``2.5 dimensional'' streamwise-independent solutions referred to as streaks.