Simin Nasseri

On the path and efficiency of two micromachines with rigid tails

This paper reports on the results of investigation of the swimming of two different micro-machines. Mechanically each of these micro-machines consists of a head (containing an electromechanical power source) and a tail which moves relative to the head as a rigid body. The problem is approached theoretically by considering the types of movement which can occur for these micro-machines immersed in a viscous medium. The first micro-machine has a tail which oscillates in vertical plane, therefore the trajectory of this machine is in that plane too. The tail of the second micro-machine roates conically, so it produces a three dimensional helical path in space with its axis approximately along the direction of tail centreline.Using the boundary element method for solving the traction equations on the surface of the tail, and a time-dependent Euler kinematic scheme to plot the path, the net propulsive force and torque, the translational velocity, angular velocity and the trajectory of each machine are calculated. Evaluation of the path and the direction of motion for each micro-machine using different dimensional parameters can give an idea of the efficiency for such machines with rigid tails.