Experimental Investigation of Thermo-Oscillatory Convection

The thermal convection in an air column oscillating with a high frequency in a plane channel whose boundaries are isothermal and have different temperatures is investigated. The experiments were performed for various channel orientations and for a wide range of nondimensional governing parameters, i.e. the gravitational Rayleigh number and the thermo-oscillatory parameter. As follows from the experimental results, for relatively large oscillation amplitudes the latter parameter characterizes the average action of high-frequency oscillations on a non-isothermal incompressible fluid. The regions in which either the thermo-oscillatory or gravitational mechanism of thermal convection predominates are determined. The threshold of excitation of thermo-oscillatory convection under weightlessness conditions is found.