A CFD Study on a Biomimetic Flexible Two-body System

By studying the characteristics of the flow field around a swimming fish,useful insights can be obtained into the superior swimming capabilities developed by nature over millions of years,in comparison to what can be achieved using the standard engineering principles traditionally employed in naval and ocean engineering.In the present study,the flow field related to a single joint fish model is simulated in the framework of a commercial computational fluid dynamics software(ANSYS Fluent 18.0).The principle of the anti-Kármán vortex street is analyzed and the relationship between the direction of the tail vortex and the direction of the fin swing is determined according to the vortex structures and the pressure distribution.A parametric investigation is finally conducted to analyze in particular how the Strouhal number(St)can affect the fish propulsive performance and efficiency。