Effect of vertical large eddy breakup devices on the drag of a flat plate

Experiments are performed to study the possibility of decreasing the net drag of a flat plate with the use of streamwise-oriented vertical elements mounted normal to the surface in an incompressible equilibrium turbulent boundary layer. The Reynolds number based on the boundary-layer momentum thickness in the section where the vertical elements are placed is 820. It is demonstrated that vertical large eddy breakup elements with the geometry used do not reduce the drag of a flat plate in the major part of the range of Reynolds numbers Re _x examined. It is only at extremely low values of Re _x that a certain gain in the net drag is reached, as compared with the value for a non-modified flow.