A Dissipative Particle Dynamics Model For Calculating the Pressure and the Viscous Drag Forces For the Flow Around the Colonies of Microorganisms

In nature, microorganisms are swimming in the water at very low reynolds numbers. when they make the colonies, the reynolds number has been increased even more than 10. in the following paper, the colonies of the microorganisms are modeled by a micro-cylinder and the flow field and the drag forces around this cylinder have been computed. to obtain more physical results and to determine the viscous and pressure drag forces, the dissipative particle dynamics method (dpd) has been applied. to validate the numerical method and the boundary conditions, two benchmark problems, i.e. lid-driven cavity flow and the fully developed channel flow, have been considered. the flow field around the micro-cylinder is also carried out at four reynolds numbers (10, 15, 20, and 25) and the results are compared with the experimental and the numerical results. the velocity and vorticity contours and profiles are presented and the dpd results are in close agreement with fem. in the last part, the total, pressure, and viscous drag forces are obtained in different reynolds numbers and the relation between intermolecular forces and the drag forces are investigated.