Research on drag reduction performance of sliding plate of rice direct seeding machine based on non-smooth structure of loach surface.

• Soil adhesion and resistance of soil-engaging components in paddy field are difficult problems. • Loach body surface is covered by scales, the scales have ridged non-smooth structure. • Rice direct-seeding machine bionic sliding plate is constructed based on the non-smooth structure of scales. • Drag reduction rate of ridge-shaped non-smooth structure is 4.21%. • Bionic technology is applied to reduce adhesion and resistance in paddy soil environment. Sliding plate has the problems of large sliding resistance and serious soil adhesion. Loach moves freely and flexibly in mud, has highly efficient lubrication and drag reduction effects. The sliding plate of rice direct seeding machine was selected as the research object and loach as the bionic prototype. The macroscopic and microscopic structure characteristics of loach were observed, the body surface of loach was covered by scales, which had a ridged non-smooth structure. The simulation analysis of the drag reduction performance of the non-smooth structure was carried out, the maximum drag reduction rate was 2.55% at the speed of 1 m/s. A bionic sliding plate of rice direct-seeding machine was constructed based on the non-smooth structure of loach body surface, and its working performance was simulated and analyzed. The results of orthogonal test show that the order of primary and secondary factors of bionic structure parameters affecting drag reduction rate was ribbed spacing > ribbed width > ribbed height. The optimal parameter combination was ribbing height 4 mm, ribbing width 4.5 mm, ribbing spacing, and the optimal drag reduction rate was 4.21%. The results of this study can provide theoretical support for bionic design of soil-engaging components in wet and soft paddy field. [ABSTRACT FROM AUTHOR]