1 Erratum to: Nonlinear Dyn DOI 10.1007/s11071-017-3512-3

In Eqs. (3) and (7) in the original publication, duplication errors were introduced at the proofs stage. The correct equations are shown below.

$$\begin{aligned} \varPsi (x,t)=g(t),(x,t)\,\in \,\partial D \times [0,T] \end{aligned}$$
(3)
$$\begin{aligned} {\varPsi }_{m}(x,t)={f}_{m}(x){t}^{m},\quad m=0,1,2,\ldots , \end{aligned}$$
(7)