Near wake of a circular cylinder submitted to blowing – I: Boundary layers evolution

The dynamical and thermal behavior of the flow around a circular cylinder submitted to blowing is experimentally investigated. The blowing is applied through the whole surface of a porous cylinder submitted to a heated turbulent main fluid in cross-flow. Velocity, pressure and temperature profiles are determined for different injection rates and main flow temperatures for Reynolds numbers ranging from 3900 to 14 000. The velocity and temperature profiles are similarly modified with the blowing, while the injection thickens the boundary layers and modifies their shape. These evolutions lower the transfer coefficients, both dynamical (shear stress) and thermal (heat transfer), and are dependent on the location around the cylinder. The blowing impact on the wall temperature is also quantified, exibiting an excellent effectiveness of the cooling with blowing.