We have successfully applied a multiscale simulation (MSS) method [Murashima and Taniguchi, Europhys. Lett., 96, 18002 (2011)] to flows of a mono-dispersed linear entangled polymer melt in a contraction-expansion channel and in concentric cylinders. In our MSS method, a macroscopic model is coupled with a microscopic model through the velocity gradient tensor and the stress tensor. As the macroscopic model, the Smoothed Particle Hydrodynamics (SPH) method is employed, on the other hand, as the microscopic model, a slip-link model is employed. By using our MSS method, two-dimensional flows in a 4:1:4 contraction-expansion channel and axial flow in concentric cylinders are examined. From our multiscale simulations, we have evaluated detailed microscopic information that comes from the polymer chain dynamics, such as the local orientation of polymer chains, the average number of entanglements and the number density of entanglements along a polymer chain. In addition, we found that the number of entanglements generally decreases in the middle section of a polymer chain under flows. To explain this behavior, an equation for the entanglement density on a primitive path is proposed. These microscopic insights will bring us a stepping stone to design a polymer melt that has a specific property.