3D numerical simulation laminar flow parallel an infinite tubes bundle

in this article, three-dimensional numerical simulation of the steady flow of a Newtonian fluid parallel to a tube assembly with regular triangular arrangements, square and hexagon, which are infinite and there are no walls around them, have been discussed. Fluid flow equations have been solved using SIMPLE method and second-order upwind approximation by Fluent software. The solution process is that first, a uniform velocity distribution is considered on the inlet face around of tubes, and with the movement of the fluid in the parallel direction of the tubes, the flow reaches the developed state. Hydrodynamic inlet length, pressure drop, friction coefficient factor and velocity distribution were investigated according to the ratio of the distance between the centers of the tubes on the diameter. To ensure the accuracy of the simulation performance, the results of the developed part of this research have been compared with the results of valid references. The results show that the length of the hydrodynamic inlet in all arrangements is less than the length of the flow inlet inside a normal circular tube with an equivalent hydraulic diameter and the ratio of this length to the equivalent hydraulic diameter decreases with the increase of the distance between the tubes. Also, by increasing the compactivity of the tubes, or in other words, reducing the distance between the tubes, the pressure drops in the 30-degree arrangement is higher than in the 45 and 60-degree situations.