摘要：The report presents the results of an experimental study of the efficiency of reducing the local friction at gas saturation of the turbulent boundary layer (TBL) in the input section of the channel at different gravitational orientation of the wall, and its dependence on the structure of gas-liquid flow. Profiles of gas concentration have a peak near the wall, which increases with the gas flow increase. The growth of concentration in the near-wall zone leads to rapid coalescence of bubbles, as a result of which the flow in TBL transits to the film-bubble regime with increasing the buoyancy effect of the gas phase, especially at low flow rates. It is shown that the key parameter of friction reduction by gas saturation is the gas phase concentration in the inner region of the boundary layer, whose magnitude is determined by the gas flow rate, the flow velocity, the distance downstream behind the gas generator, and the gravitational orientation of the wall.
