The state of two-phase flow "liquid-gas" has been modeled numerically by the three-dimensional finite volumes method of complex research of heat and mass transfer. This allows examining the interaction of some transfer processes in the natural cooling basin (lake Druksiai): power and direction of the wind, variable density of the water, heat conduction and heat transfer coefficient of the water-air interface. The interphase source contains the diffusive (e.g., friction, heat transfer) and convective (mass transfer related) links between the phases. The air mixing rate at the water surface is caused by natural space - time variation of the wind, and can be described by the value of eddy viscosity coefficient − 1 m2s (numerical modeling it used 0.9−1.3 m2/s). The model is applying for weakly wind, approximately 1−5 m/s of the mean wind velocity.
A comparison experimental and numerical result showed a qualitative agreement.