Hydrodynamic response of separated undulating fins based on numerical simulation and orthogonal experiment: Analysis and optimization of thrust influencing factors

The purpose of this study is to investigate the factors influencing the thrust enhancement phenomenon in separated undulating fins and to elucidate the underlying mechanisms. Numerical simulations were employed to conduct an Orthogonal testal study on the thrust and thrust enhancement efficiency of separated undulating fins under the influence of multiple factors. The effects of variables such as oscillation angle, wave number, and phase on thrust enhancement were comprehensively analyzed. The results indicate that variations in the oscillation angle most significantly impact the thrust, showing a positive correlation between the two. In terms of thrust enhancement efficiency, changes in the wave number are particularly notable, displaying a negative correlation. Under optimal conditions, the thrust enhancement efficiency of the separated undulating fins reached 23.42 %. It is important to note that phase alterations primarily affect the instantaneous thrust enhancement efficiency, with minimal impact on the average thrust enhancement efficiency. Flow field analysis revealed that thrust enhancement is associated with the region influenced by vortices. As the wave number increases, this region decreases significantly. This study provides new insights into the enhancement of thrust by undulating fins.