| 摘要 |
To modify a turbulent boundary layer flow over a surface to reduce its drag, a series of streamwise riblet projections are provided on the surface. The heights, and possibly also the pitches, of the projections are increased progressively in the downstream direction to mitigate the self-limiting effect of the projections as they establish a raised virtual wall surface for the turbulent boundary layer. The increase may be made, continuously or in one or more steps. |
