乌贼喷射过程的数值模拟

Numerical simulation of squids jetting process

为了研究乌贼喷水过程中的流场状态,为仿生乌贼机器人的研究提供理论基础,用CFD软件对乌贼的喷水过程进行了数值模拟.建立了简化的乌贼身体模型,用动网格技术模拟外套膜的收缩动作,对其二维轴对称、不可压缩、层流时的瞬态Navier-Stokes方程进行数值求解,仿真不同的外套膜收缩速度及不同直径喷嘴喷射后涡流环的形成发展过程,验证临界涡流环的存在条件为涡流环形成数为4,同时还对喷射过程中所受到的推进力进行了相应的对比计算.结果表明,该计算模型能较好反映乌贼喷射过程,数值模拟结果与文献中实验结果基本吻合.

For researching the flow distribution of squids jetting process, and providing theoretic basis for biomimetic robot, the numerical simulations of this process were studied by CFD. A simplified body of squids was modeled, and the mantle motion during escape-jet locomotion was explicitly included into the simulations by using a deforming mesh. By solving the 2D-axisymmetric, incompressible, laminar, unsteady Navier-Stokes equations, different vortex evolution behavior was observed depending on different mantle contraction rate and jet diameter, and the exiting condition of the critical vortex ring, the formation number L/D = 4, was verified. The calculations of corresponding instantaneous forces during the ejecting have also been carried out. The re- sults show that this model is suitable to simulate jet process of squids and the numerical results are in satisfactory agreements with the experiment data.