MIXED CONVECTION OVER A COOLED HORIZONTAL PLATE - NONUNIQUENESS AND NUMERICAL INSTABILITIES OF THE BOUNDARY-LAYER EQUATIONS

The boundary-layer flow over a cooled horizontal plate is considered. It is shown that the real part of the spectrum of the evolution operat or of the linearized equations is not bounded uniformly from above whi ch explains the difficulties encounterd by a numerical solution. Furth ermore it is shown that near the leading edge an asymptotic expansion of the solution is not unique. A one-parametric family of asymptotic e xpansions of solutions can be constructed.