Monkewitz, Peter AlexisGrandjean, Emeric2008-05-222008-05-222008-05-22200810.5075/epfl-thesis-4144https://infoscience.epfl.ch/handle/20.500.14299/25895urn:nbn:ch:bel-epfl-thesis4144-0An experimental study of the stability of the Rayleigh-Bénard-Poiseuille flow was performed in a large transverse aspect ratio channel. The onset for the transverse thermo-convective rolls was determined as a function of the Reynolds number for two different fluids (water: Pr = 6.5 and mineral oil: Pr = 450). Then, the system impulse response was studied and a good agreement with theory was found for the convective/absolute instability transition. Finally the response of the system to localized heating was observed and compared with analytical and numerical results by Martinand, Carrière and Monkewitz (2004 & 2006): experimental thermo-convective global modes are found to correspond to the saturated "steep" variety constructed by Pier, Huerre and Chomaz (2001).enRayleigh–Bénard–Poiseuillethermal convectionabsolute/convective instabilityglobal modeSchlierenRayleigh–Bénard–Poiseuilleconvection thermiqueinstabilité convective/absoluemode globalSchlierenthesis::doctoral thesis