Pattern formation in a slowly flattening spherical cap: delayed bifurcation

This article describes a reduction of a nonautonomous Brusselator reaction-diffusion system of partial differential equations on a spherical cap with time dependent curvature using the method of centre manifold reduction. Parameter values are chosen such that the change in curvature would cross critical values which would change the stability of the patternless solution in the constant domain case. The evolving domain functions and quasi-patternless solutions are derived as well as a method to obtain this nonautonomous normal form. The coefficients of such a normal form are computed and the reduction solutions are compared to numerical solutions.