Numerical investigation of drag reduction characteristics of flexible plate based on two way fluid-structure interaction

To investigate the drag reduction characteristics of a flexible plate, a numerical simulation analysis was per-formed on the relationships of flexibility and thickness of a flexible plate on the effect of drag reduction. To accurately demonstrate the mutual interaction between flexible and fluid flows and capture the moving boundary of the plate, a bidirectional fluid-structure interaction (FSI) method was developed. The numerical results demonstrated that the flexible plate played a positive role in drag reduction. The drag reduction effect could be improved by increasing the flexibility of the plate or decreasing its thickness. Moreover, the pressure-difference resistance acting on the flexible plate was negative, indicating that the existence of pressure resistance was favorable for drag reduction. Further, the numerical results revealed that the real contribution to the drag reduction lay at the middle part of the flexible plate, i.e., the part with the significant deformation, whereas the parts with small deformation exerted little effect on the drag reduction. The conclusions from this study can provide guidance for future investigation of FSI problem and flexible surface-drag-reduction technology.