Oscillatory travelling wave solutions for coagulation equations

Abstract

We consider Smoluchowski's coagulation equation with kernels of homogeneity one of the form $K_{\epsilon }(\xi ,\eta )=({\xi }^{1-\epsilon }+{\eta }^{1-\epsilon })(\xi \eta {)}^{\frac{\epsilon }{2}}$. Heuristically, in suitable exponential variables, one can argue that in this case the long-time behaviour of solutions is similar to the inviscid Burgers equation and that for Riemann data solutions converge to a traveling wave for large times. Numerical simulations in \cite{HNV16} indeed support this conjecture, but also reveal that the traveling waves are oscillatory and the oscillations become stronger with smaller $\epsilon$. The goal of this paper is to construct such oscillatory traveling wave solutions and provide details of their shape via formal matched asymptotic expansions.