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This article is cited in 27 scientific papers (total in 27 papers)
Stabilization of solutions of the first mixed problem for a parabolic equation of second order
F. Kh. Mukminov
Abstract:
The behavior for large time of the solution $u(t,x)$ in an unbounded domain $\Omega\subset R_n$ of the first mixed problem for the parabolic equation
\begin{gather}
u_t=(a_{ij}(t,x)u_{x_j})_{x_i},\qquad(t,x)\in(t>0)\times\Omega,\\
\gamma^{-1}|y|^2\leqslant a_{ij}(t,x)y_iy_j\leqslant\gamma|y|^2,
\end{gather}
with initial function $\varphi$, $\operatorname{supp}\varphi\subset K_{R_0}$, $K_r=\{|x|<r\}$, is investigated. It is shown that the function $\lambda(r)$, which for each fixed $r$ is the first eigenvalue of the Dirichlet problem for the operator $-\Delta$ in $\Omega_r=\Omega\cap K_r$, for a certain class of domains determines the rate at which the solution $u(t,x)$ tends to zero as $t\to\infty$. Namely, let $r(t)$ be the function inverse to the monotone increasing function $F(r)=r/\sqrt{\lambda(r)}$. Then for all $t\geqslant T$ and all $x$ in $\Omega$
\begin{equation}
|u(t,x)|\leqslant M\exp\biggl(-\varkappa\,\frac{r^2(t)}t\biggr)\|\varphi\|_{L_2(\Omega)}.
\end{equation}
Here the constant $\varkappa$ depends only on $n$ and $\gamma$ of (2), while $T$ and $M$ depend on $\Omega$, $\gamma$, and $R_0$. It is proved that for a certain class of domains the estimate (3) is in a sense best possible.
Bibliography: 13 titles.
Received: 23.10.1979
Citation:
F. Kh. Mukminov, “Stabilization of solutions of the first mixed problem for a parabolic equation of second order”, Math. USSR-Sb., 39:4 (1981), 449–467
Linking options:
https://www.mathnet.ru/eng/sm2613https://doi.org/10.1070/SM1981v039n04ABEH001527 https://www.mathnet.ru/eng/sm/v153/i4/p503
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