Drag Reduction of a Turbulent Boundary Layer over an Oscillating Wall and Its Variation with Reynolds Number

Figure 4

The variation of DR in the downstream direction. (Black, solid) DR from DNS. (Red, broken) DR from (18). (Green, broken) DR from (17). (Blue, broken) DR from (26). (Blue, solid) DR from (26) with from expression (29) (). (Cyan, solid) DR from expression (30).