Progress in rough-wall turbulence

Exploring the statistics and structural characteristics of rough-wall turbulence is of vital importance and essence to the turbulence theory and engineering application. A well-established theory in the rough-wall turbulence study was the wall similarity hypothesis, to which the latest finding of the inner-outer layer interaction between structures with different scales brings a severe challenge. Consequently, the validation of the hypothesis became a hot topic. In views of the current status, the present paper reviews recent major achievements in the rough-wall turbulence at home and abroad, and the possible contents in later research are further discussed.