A damped semilinear hyperbolic equation on 1 with linear memory is considered in a history space setting. Viewing the past history of the displacement as a variable of the system, it is possible to express the solution in terms of a strongly continuous process of continuous operators on a suitable H
On the Linear Damped Wave Equation
✍ Scribed by Julián López-Gómez
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 864 KB
- Volume
- 134
- Category
- Article
- ISSN
- 0022-0396
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✦ Synopsis
In this work we estimate the spectrum of the linear damped wave semigroup under homogeneous Dirichlet boundary conditions by using the principal eigenvalue of an elliptic operator related to the equation. Our estimate is optimal for real eigenvalues. Then, we analyze the behavior of the estimate as the damping amplitude grows to infinity. When the damping changes of sign we extend a result of Freitas [5] to show that the semigroup possesses at least two real eigenvalues greater than one if the amplitude is sufficiently large. In particular, the trivial state is unstable, in strong contrast with the sign definited case. Finally, we characterize the limiting behavior of the real eigenpairs which originate the inestability of the trivial state. This analysis is based upon the behavior of the principal eigenpair of a singular perturbation problem at the singular limit. Our theory is of interest by itself and it has many applications to reaction diffusion systems (c.f. for instance [6]).
📜 SIMILAR VOLUMES
We employ elliptic regularization and monotone method. We consider X⊂R n (n 1) an open bounded set that has regular boundary C and Q = X×(0,T), T>0, a cylinder of R n+1 with lateral boundary R = C×(0,T).
## Abstract We present a global existence theorem for solutions of __u__^__tt__^ − ∂~__i__~__a__~__ik__~ (__x__)∂~__k__~__u__ + u~t~ = ƒ(__t__, __x__, __u__, __u__~__t__~, ∇__u__, ∇__u__~__t__~, ∇^2^__u__), __u__(__t__ = 0) = __u__^0^, __u__(=0)=__u__^1^, __u__(__t, x__), __t__ ⪖ 0, __x__ϵΩ.Ω equal
The existence and estimate of the upper bound of the Hausdorff dimension of the global attractor for the strongly damped nonlinear wave equation with the Dirichlet boundary condition are considered by introducing a new norm in the phase space. The gained Hausdorff dimension decreases as the damping