Numerical Study of the Fish-like Robot Swimming in Fluid with High Reynolds Number: Immersed Boundary Method

Abstract

Fish-like robots have been widely used in intelligent surveillance and investigation because of their high swimming efficiency and low traveling noise. Numerical simulations are usually selected to simulate the movement modes and hydrodynamic characteristics of fish-like robots during design and manufacture. However, the body-fitted grid method traditionally utilized in numerical simulations often has difficulty dealing with moving solid boundaries. In this work, the immersed boundary method, superior in handling the moving boundary conditions, is employed to simulate the movement of a fish-like robot swimming in high Reynolds number flows in combination with the RANS turbulence model. The numerical method is first validated using a fluid flowing over a square block, and the corresponding results are in good agreement with the ones reported in reference. Then, the swing of the fish-like robot under three different Reynolds numbers is studied. The lift coefficient and the drag coefficient of the fish-like robot decrease with increasing the Reynolds number. This paper provides remarkable support for future designs and applications of fish-like robots.

Dynamics, stability and bifurcations of a planar three-link swimmer with passive visco-elastic joint using “ideal fluid” model

“…The numerical solution is denoted by solid curves and the analytical solution is denoted by dashed-dotted curves. It is possible to see that there exist two asymmetric solutions for the system in (44). There is a very good agreement in the bifurcation frequency, and a qualitative agreement for larger frequencies, where as we are moving away from the bifurcation frequency the approximation deviates from the numerical solution.…”

“…In Fig. 12 we show the mean angle θ1 versus frequency obtained by numerical simulation (see Section 4.2), compared with the approximate analytic solution obtained by finding a 0 from the solution of ( 43) and (44). The blue and red colors represent symmetric and asymmetric branches, respectively.…”

“…From equation (A5) one can see that M 1 and N 1 depend only on a 2 0 , but not on a 0 , thus the system in (44) possesses two solutions which are a reflection of each other, with a positive or a negative mean of the same magnitude. Therefore, it is possible to solve the system in (44) by elimination of the variables a 0 and a 1 , which reduces to a fourth order polynomial in b 1 , whose roots can be found numerically.…”

“…In order to understand the motion of swimming robots and improve their efficiency and locomotive performance, one needs to use mathematical models of their motion and interaction with the surrounding fluid. The full detailed equations of the flow coupled with the robot's motion are highly complicated and require extensive numerical computation [44]. Therefore, it is important to find simplified lowdimensional models which capture the main hydromechanical and dynamical effects [3].…”

Laminar Flow Analysis of NACA 4412 Airfoil Through ANSYS Fluent

“…Here, A is denoted as aerodynamic force, which is the force exerted on the airfoil by air due to the relative motion of the airfoil and air [11].…”