基于浸入边界法的鱼体自主游动的数值模拟

对游动或飞行生物自主运动特性的深入研究,可促进仿生学的进一步发展。本文以"C"型游动鱼作为研究对象,建立了自主游动的柔性鱼模型。此模型较为真实地反映了鱼自主游动时鱼体内力(由鱼体肌肉收缩提供)、鱼体运动和外界流体之间的耦合作用。基于传统的反馈力方法和混合有限元浸入边界法对鱼的自主游动进行了数值模拟。分析了鱼自主游动启动阶段和巡游阶段流场特性及鱼体运动特征。模拟结果表明,受到鱼体自身组织结构和外界流场作用,鱼游动时通过呈"C"型和类"S"型的不断转换,以获取能量,实现鱼体自主游动。

Numerical investigation of freely self-propelled flexible fish using immersed boundary method

Study on the motion performance of interaction between a swimming or flying creatures and fluid,usually applied to reveal the biological mechanism of mechanics and movement.A "C" type swimming fish as the research object,a flexible model of freely self-propelled swimming fish is established.This model can reflected truly the interaction among fish movement,internal force and the external fluid.Using hybrid finite difference/finite element immersed boundary method combined with traditional feedback force method,the movement of a swimming fish is simulated.The hydrodynamic performance of start-up and cruise process of a swimming fish is analyzed.The results reveal that the conversion of "C" type and "S" type of fish body can improve the efficiency of the fish swimming,and the conversion of "C" type and "S" type is mainly affected by structure of fish body and flow field.