数学物理学报(英文版) ›› 2013, Vol. 33 ›› Issue (4): 1031-1048.doi: 10.1016/S0252-9602(13)60061-2

• 论文 • 上一篇    下一篇

ON THE CAUCHY PROBLEM FOR A REACTION-DIFFUSION SYSTEM WITH SINGULAR NONLINEARITY

周军   

  1. School of Mathematics and Statistics, Southwest University, Chongqing 400715, China
  • 收稿日期:2012-05-22 修回日期:2012-09-26 出版日期:2013-07-20 发布日期:2013-07-20
  • 基金资助:

    This research was supported by NSFC (11201380), the Fundamental Research Funds for the Central Universities (XDJK2012B007), Doctor Fund of Southwest University (SWU111021) and Educational Fund of Southwest University (2010JY053).

ON THE CAUCHY PROBLEM FOR A REACTION-DIFFUSION SYSTEM WITH SINGULAR NONLINEARITY

 ZHOU Jun   

  1. School of Mathematics and Statistics, Southwest University, Chongqing 400715, China
  • Received:2012-05-22 Revised:2012-09-26 Online:2013-07-20 Published:2013-07-20
  • Supported by:

    This research was supported by NSFC (11201380), the Fundamental Research Funds for the Central Universities (XDJK2012B007), Doctor Fund of Southwest University (SWU111021) and Educational Fund of Southwest University (2010JY053).

摘要:

We consider the growth rate and quenching rate of the following problem with singular nonlinearity
ut = △uv−λ, vt = △vuμ, (x, t) ∈ Rn × (0,∞),
u(x, 0) = u0(x), v(x, 0) = v0(x), xRn
for any n ≥ 1, where λ, μ > 0 are constants. More precisely, for any u0(x), v0(x) satisfying A11(1+|x|2α11u0A12(1+|x|2α12 , A21(1+|x|2α21v0A22(1+|x|2α22 for some constants α12 ≥ α11, α22 ≥α 21, A12A11, A22A21, the global solution (u, v) exists and satisfies A11(1+|x|2+b1tα11 uA12(1+|x|2+b2tα12 , A21(1+|x|2+b1tα21 v A22(1+|x|2+b2tα22 for some positive constants b1, b2 (see Theorem 3.3 for the parameters Aijαij , bi, i, j = 1, 2). When (1 − λ)(1 − λμ) > 0, (1 − λ)(1 − λμ) > 0 and 0 < u0A1(b1T +|x|2)1−λ/1−λμ , 0 < v0A2(b2T +|x|2)1−μ/1−λμ in Rn for some constants Ai, bi (i = 1, 2)satisfying A−λ2 > 2nA11−λ/1−λμ , Aμ1 > 2nA21−μ/1−λμ and 0 < b1 ≤ (1−λμ)A−λ2−(1−λ)2nA1/(1−λ)A1, 0 < b2 ≤ (1−λμ)Aμ1−(1−μ)2nA2/(1−μ)A2, we prove that u(x, t) ≤ A1(b1(Tt)+|x|2)1−λ/1−λμ , v(x, t) ≤A2(b2(Tt) + |x|2)1−μ/1−λμ in Rn × (0, T). Hence, the solution (u, v) quenches at the origin x = 0 at the same time T (see Theorem 4.3). We also find various other conditions for the solution to quench in a finite time and obtain the corresponding decay rate of the solution near the quenching time.

关键词: Cauchy problems, singular nonlinearity, growth rate, quenching rate

Abstract:

We consider the growth rate and quenching rate of the following problem with singular nonlinearity
ut = △uv−λ, vt = △vuμ, (x, t) ∈ Rn × (0,∞),
u(x, 0) = u0(x), v(x, 0) = v0(x), xRn
for any n ≥ 1, where λ, μ > 0 are constants. More precisely, for any u0(x), v0(x) satisfying A11(1+|x|2α11u0A12(1+|x|2α12 , A21(1+|x|2α21v0A22(1+|x|2α22 for some constants α12 ≥ α11, α22 ≥α 21, A12A11, A22A21, the global solution (u, v) exists and satisfies A11(1+|x|2+b1tα11 uA12(1+|x|2+b2tα12 , A21(1+|x|2+b1tα21 v A22(1+|x|2+b2tα22 for some positive constants b1, b2 (see Theorem 3.3 for the parameters Aijαij , bi, i, j = 1, 2). When (1 − λ)(1 − λμ) > 0, (1 − λ)(1 − λμ) > 0 and 0 < u0A1(b1T +|x|2)1−λ/1−λμ , 0 < v0A2(b2T +|x|2)1−μ/1−λμ in Rn for some constants Ai, bi (i = 1, 2)satisfying A−λ2 > 2nA11−λ/1−λμ , Aμ1 > 2nA21−μ/1−λμ and 0 < b1 ≤ (1−λμ)A−λ2−(1−λ)2nA1/(1−λ)A1, 0 < b2 ≤ (1−λμ)Aμ1−(1−μ)2nA2/(1−μ)A2, we prove that u(x, t) ≤ A1(b1(Tt)+|x|2)1−λ/1−λμ , v(x, t) ≤A2(b2(Tt) + |x|2)1−μ/1−λμ in Rn × (0, T). Hence, the solution (u, v) quenches at the origin x = 0 at the same time T (see Theorem 4.3). We also find various other conditions for the solution to quench in a finite time and obtain the corresponding decay rate of the solution near the quenching time.

Key words: Cauchy problems, singular nonlinearity, growth rate, quenching rate

中图分类号: 

  • 35B35