Engineering Physics Annotation << Back CONVECTION IN A LAYER OF THE WATER, CAUSED BY THE ELECTROMAGNETIC WAVE. II. ONSET OF CONVECTION O.A. SINKEVICH, E.I. ZUBKOV, J.S. KORSHUNOV The fi rst part of the paper problems of stationary heating of salt water layer by absorption of electromagnetic radiation were examined. It was considered, that on a free surface there is a turbulent heat exchange to air surrounding a layer and two possible thermal modes on the bottom surface of a liquid layer (isothermal and adiabatic) are investigated. For all modes, conditions of a stationary heating are established. It is shown, that due to the nonlinearity of the Joule heating exist regimes in which the bottom layers of a liquid are heated up more strongly, than top. The nonlinearity of the Joule heat is connected with the fact that the conductivity of the water, which determines the absorption of electromagnetic waves depends on the temperature conditions were established the existence of a stationary heating fl uid at res. The stability of stationary modes of liquid heating with respect to small perturbations was investigated using the Boussinesq approximation. Analysis of convection is carried out considering the thermal expansion of the liquid and the Joule heat perturbation. It is found that the stationary water heating regimes may not be stable and the convection can occur. In the space of the operating parameters (the Rayleigh number, the wavelength of the perturbation, the Nusselt number, the intensity of the Joule heating and electromagnetic wave frequency) set the boundaries of occurrence of thermal convection. It is shown that the joint effects (thermal expansion and the Joule heating) are decreasing the critical Rayleigh number responsible for the onset of convection. Key words: Electromagnetic wave, see water, flat layer, Joule’s heating, stationary modes, non-uniform heating, stability, convection, Boussinesq approximation, neutral curve, critical Rayleigh number. Contacts: E-mail: Oleg.sinkevich@itf.mpei.ac.ru Pp. 46-58.