利用扩展的双曲函数法得到了combined KdV-mKdV(cKdV)方程的几类精确解,其中一类为具有扭结-反扭结状结构的双扭结单孤子解.在不同的极限情况下,该解分别退化为cKdV方程的扭结状或钟状孤波解.理论分析表明,cKdV方程既有传播型孤立波解,也有非传播型孤立波解.文中对双扭结型孤立波解的稳定性进行了数值研究,结果表明,cKdV方程既存在稳定的双扭结型孤立波,也存在不稳定的双扭结型孤立波.
Based on the ideas of the hyperbola function expansion method,we obtained some analytical solutions of the combined KdV-mKdV (cKdV) equations by introducing new expansion functions. One of the single soliton solutions has the kink-antikink structure,and this solution reduces to the kink-like solution and the bell-like solution under different limitations. Theoretical analysis shows that the cKdV equation has both propagated-type and non-propagated-type solitary wave solutions. We also investigated the stability of the single solitary wave solution with double kinks numerically. The results indicate that the solution may be stable or unstable,depending on different sets of parameters.