Observations of convective cell-to-roll transition in evaporating liquid blown off by airflow

We present the results of laboratory studies of convective structures in a thin (5 mm) ethyl-alcohol layer blown off by airflow in a wind tunnel. The formation of structures in the working part of the alcoholfilled cuvette are determined by the destabilizing (inversion-type) temperature profile arising due to the evaporation of liquid. The design of the experimental setup ensures the unidirectional character of the current in the working part of the cuvette where structures are formed. We singled out three stages through which structures successively evolve with increasing the wind velocity: polygonal cells (no blowing), along-flow elongated cells, and along-flow aligned convective roll structures. The profiles of the average and pulsation velocities in the boundary layer over the cuvette are determined together with the drift flow velocity of the liquid at different transition stages from convective cells to rolls. The dimensionless flow parameters are estimated and the comparison of the experimental data with known theoretical results is fulfilled.