Experimental and theoretical studies of the flow around a sphere with account for gas injection from its surface

The results of the experimental and theoretical studies of the gas flow around a solid sphere under conditions of mass outflow from its surface are presented. A new experimental setup and a method for studying the flow around a solid sphere during the gas injection from its surface are proposed with the aim of improving the accuracy of determining the drag coefficient. In the range of the Reynolds number (Re = 133÷667), experimental results show that the drag coefficient decreases at the gas injection from the surface of the sphere. Moreover, the drag coefficient decreases with an increase in the density of the injected air flow at the fixed Reynolds number. Numerical simulation of a two-phase flow around a sphere with the gas injection from its surface is carried out for two calculation cases: with a uniform gas outflow from the surface of a porous sphere and with gas injection from perforated holes on the sphere surface. The numerical calculation results for the case of gas injection from the holes of the sphere are in quantitative and qualitative agreement with the experimental data.