“…In more detail, a convex splitting numerical scheme, which treats the terms of the variational derivative implicitly or explicitly according to whether the terms corresponding to the convex or concave parts of the energy, was formulated in [19], with a mixed finite element approximation in space. Such a numerical approach assures two mathematical properties: unique solvability and unconditional energy stability; also see the related works for various PDE systems, including the phase field crystal (PFC) equation [4,5,27,34,35,39], epitaxial thin film growth model [8,10,31,33], and others [21,22]. Moreover, for a gradient system coupled with fluid motion, the idea of convex splitting can still be applied and these distinguished mathematical properties are retained, as given by a few recent works [9,12,13,19,38].…”