The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are ob...The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed.展开更多
Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied ex...Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied experimentally in a 160×160-mm^2 cavity that ＆ heated from the bottom block. The convection pattern ＆ visualized by an infrared thermography camera. It is shown that the onset of the Benard cell is consistent with theoretical analysis. The wavenumber decreases obviously with increasing temperature, except for a slight increase near the onset. The wavenumber gradually approaches the minimum when the supercritical number e is larger than 10. Finally, a formula is devised to describe the wavenumber selection in supercritical convection.展开更多
文摘The effects of electric field and non-uniform basic temperature gradient on the onset of Rayleigh-Bénard-Marangoni convection in a micropolar fluid are studied using the Galerkin technique. The eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The microrotation is assumed to vanish at the boundaries. A linear stability analysis is performed. The influence of various micropolar fluid parameters and electric Rayleigh number on the onset of convection has been analysed. Six different non-uniform temperature profiles are considered and their comparative influence on onset is discussed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11502271 and 11372328the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences under Grant Nos XDA04020405 and XDA04020202-05the China Manned Space Engineering Program
文摘Marangoni Benard convection, which is mainly driven by the thermocapillary （Marangoni） effect, occurs in a thin liquid layer heated uniformly from the bottom. The wavenumber of supercritical convection is studied experimentally in a 160×160-mm^2 cavity that ＆ heated from the bottom block. The convection pattern ＆ visualized by an infrared thermography camera. It is shown that the onset of the Benard cell is consistent with theoretical analysis. The wavenumber decreases obviously with increasing temperature, except for a slight increase near the onset. The wavenumber gradually approaches the minimum when the supercritical number e is larger than 10. Finally, a formula is devised to describe the wavenumber selection in supercritical convection.
