Thermo-viscous fingering in quarter five-spot miscible displacements

A pseudo-spectral method is implemented to model thermo-viscous fingering in a quarter five-spot geometry. An exponential dependence of viscosity on temperature and concentration is represented by two parameters βTβT and βCβC, respectively. The effects of these two parameters as well as that of the thermal lag coefficient and the Lewis number on the flow development are analyzed. Time evolutions of nonlinear fingers are examined qualitatively by plotting concentration and temperature iso-surfaces. The qualitative observations are further substantiated through an examination of the relative contributions of solutal and thermal vorticity components in the development of the instability. This study reveals that the strong velocity gradients in this radial geometry and the coupling of heat and mass transfer result in some important differences with what is obtained in the case of the rectilinear geometry.