Review of Research on Drag Reduction of Non-smooth Surface

The non-smooth surface drag reduction technology based on the research and development of bionics has broad applications in the fields of marine engineering equipment and high-tech ships and has attracted the attention of scholars. In the work, research methods for fabricating non-smooth surface to achieve drag reduction were firstly summarized. Three non-smooth surfaces, riblets, dimples and compliant, were enumerated and discussed in detail. The influence of the geometric parameters, shape and arrangement of the riblets on the drag reduction effect were illustrated and turbulent drag reduction theory was revealed accordingly. The drag reduction effect on the rotating body, flat plate and streamline body was analyzed, when these surfaces were dimpled and applied in turbulent flow. Basing on the theoretical model of self-adaption surface, the effect of wall motion on the flow transition and turbulent structure was described, and then the drag reduction effect of the compliant surface was disclosed. Finally, the drag reduction effect of three types of non-smooth surfaces and the development status of the drag reduction mechanism were summarized. Problems that non-smooth surface drag reduction needs to be solved in future research were pointed out. Non-smooth surfaces have great engineering value and broad application prospects in the light of research and practical results. This paper aims not only to thoroughly understand the drag reduction of non-smooth surfaces in a more specific and comprehensive way, but also provide the necessary theoretical basis for improving the present drag reduction and energy saving technology.