“…While there have been extensive numerical works for the given model [9,11,12,16,17,24,43], a theoretical justification of the smoothness and analyticity for the PDE solution has been limited. To obtain a PDE solution with real analytic regularity, the Gevrey norm has been a widely-used tool for the analysis for many time-dependent nonlinear PDEs; see the related works for 2-D and 3-D incompressible Navier-Stokes equation [4,19], Kuramoto-Sivashinsky equation [3], nonlinear parabolic equation [8,18], 3-D Navier-Stokes-Voigt equation [26], porous media flow [34]. Other than the Gevrey regularity solutions, a more general class of analytic solutions for different models of incompressible fluid have been discussed in [5,23,27,28,29,30,31,32], etc.…”