I used my IDL program "iso.pro" to plot the results obtained at time t=0.00, t=0.02, t=0.04, ...t=0.1 .

I opted to graph the results at the isosurface level 0.6 as this gave reasonable results throughtout the whole time period.

The results that follow are for a uniform flow,

and with the coefficient of del_squared set at 0.2