Improvement of Dissipative Particle Dynamics method by taking into account the particle size

Abstract

In this paper, ow past a single Dissipative Particle Dynamics (DPD) particle with low Reynolds number is investigated and whether a single DPD particle immersed in a uid has an intrinsic size is surveyed. Then, a minimum length scale is determined such that the hydrodynamic behavior based on standard DPD formulation is modeled correctly. Almost all of the previous studies assume the DPD particles as point centers of repulsion with no intrinsic size. Hence, to prescribe the size of a simulating sphere, a structure for frozen DPD particles is proposed. In this paper, two e ective radii, namely Stokes-Einstein radius and a radius based on the Stokes law, for DPD particles are introduced. For small Reynolds numbers, it was proved that the two radii approached each other. Finally, in spite of the typical simulations which assume DPD particles as point centers of repulsion, it was concluded that each of the individual DPD particles interacted with other particles as a sphere with non-zero radius. This resulted in reduction in the required number of particles and led to more economical simulations. Contemplating the radius of the particles was necessary for the new low-dimensional model, which was derived from the DPD method.

Microscopic mechanism study of the rheological behavior of non-Newtonian fluids based on dissipative particle dynamics

“…The Stokes-Einstein equation derived by combining eqn (13) and (16) was applied to describe the Brownian motion of a material sphere in a viscous fluid. In the DPD method study, Pan et al 52 and Yaghoubi et al 53 demonstrated the existence of hydrodynamic radii for the simplified beads at low Reynolds number conditions. In macroscopic studies, the viscous medium adheres to the surface of the spherical material to form a thin film, but its thickness is much smaller than the spherical radius a and thus neglected, but in mesoscopic and microscopic studies, the thickness of the film formed by the polymer cannot be neglected compared to the nanoscale radius of the spherical material.…”

Numerical Simulation of Water Drop Deformation Under Electrical Fields in Oil Fields

“…In the future, energy and the environment are the two main concerns, and it is essential to develop sustainable renewable energy technologies [5,6]. However, in many countries, they still use oil and gas sources to supply their energy needs [7,8].…”