| Abstract: | The presence of Tollmien-Schlichting waves during the initial stages of the isothermal mixing of two axi-symmetical laminar streams of air has been confirmed by comparing data from hot wire measurements with published two-dimensional theoretical and experimental results for the stability of mixing and for transition in a boundary layer. Hot wire measurements in the flow field of steady or vibrating axi-symmetrical laminar diffusion flames are remarkably similar to those obtained during isothermal mixing. A travelling wave in the mean flow direction has also been established. Data for these flames agree with the results of a higher order stability analysis for natural convection flow past a vertical heated plate. It has been concluded that Tollmien-Schlichting waves are responsible for exciting flame vibrations. |
