Zhijian Yang

Global existence of solutions for quasi-linear wave equations with viscous damping

In this paper, the global existence of solutions to the initial boundary value problem for a class of quasi-linear wave equations with viscous damping and source terms is studied by using a combination of Galerkin approximations, compactness, and monotonicity methods.

Blowup of solutions for improved Boussinesq type equation

The paper studies the existence and uniqueness of local solutions and the blowup of solutions to the initial boundary value problem for improved Boussinesq type equation utt−uxx−uxxtt=σ(u)xx. By a Galerkin approximation scheme combined with the continuation of solutions step by step and the Fourier transform method, it proves that under rather mild conditions on initial data, the above-mentioned problem admits a unique generalized solution u∈W2,∞([0,T];H2(0,1)) as long as σ∈C2(R). In particular, when σ(s)=asp, where a≠0 is a real number and p>1 is an integer, specially a<0 if p is an odd number, the solution blows up in finite time. Moreover, two examples of blowup are obtained numerically.

Blowup of solutions for the bad Boussinesq-type equation

Abstract The paper studies the blowup of solutions to the initial boundary value problem for the “bad” Boussinesq-type equation u tt − u xx − bu xxxx = σ ( u ) xx , where b >0 is a real number and σ ( s ) is a given nonlinear function. By virtue of the energy method and the Fourier transform method, respectively, it proves that under certain assumptions on σ ( s ) and initial data, the generalized solutions of the above-mentioned problem blow up in finite time. And a few examples are shown, especially for the “bad” Boussinesq equation, two examples of blowup of solutions are obtained numerically.