Higher order stability effects in a natural convection boundary layer over a vertical heated wall

Boundary layer instability of the natural convection flow on a uniformly heated vertical plate

“…They found excellent agreement for the critical Rayleigh number predictions between the parallel and non-parallel approaches for the higher unstable frequencies, but not for the lower unstable frequencies. Severin and Herwig [27], also using a similar parabolized stability method, obtained separate neutral stability curves for the temperature and stream-wise velocity disturbances, with a variation of approximately 75% in the critical Grashof number and 100% in the critical frequency. Further, these studies quantified the flow instability using the disturbance amplitude wall-normal integral which they referred as the ''net-disturbance''.…”