Abstract: In lhis paper experimental research is carried out for the existence of larqe andsmall scale.structures in turbulent boundary layer and the interactions between these structures. Based on the experimental results,a new method is suggested to discribe the coherent strucures in which the interactions between between the coherent and small-scale slructures are considered,Using this method a new pattern recognition method is and rough wall conditions. The results show that the suggested method is reasonable.

Key words: coherent structures, small scale structures, turbulent