Stabilité de l'écoulement de Hartmann chauffé par le bas

Abstract: A numerical study is conducted in order to determine the influence of a vertical magnetic field, the Reynolds number and a temperature stratification on the instabilities occurring in the Hartmann flow heated from below. For and , the results show that the vertical magnetic field has a stabilizing effect on both transverse oscillatory travelling waves and longitudinal stationary rolls . The temperature stratification is responsible of a destabilization of the transverse modes and the appearance of longitudinal modes non-existent for the isothermal Hartmann flow. Moreover, the extent of the domains of Re where the transverse modes prevail is found to narrow when Ha increases and to widen when Ra increases for a given value of Ha. On the other hand, for the modes, the extent of the domains of Re where they prevail increases when Ha grows. To cite this article: W. Fakhfakh et al., C. R. Mecanique 334 (2006). [Copyright &y& Elsevier]