Coupled transport mechanism in simple shear flows over quadrilaterally arranged micro pillars

Through well-designed physical model and high-fidelity numerical simulation, the physics of advective heat and mass transfer over quadrilaterally arranged micro pillars has been investigated. The essential issues that have been addressed include the characteristics of a simple shear flow over quadrilateral arrays of micro pillars, the effect of fluid inertia and the effect of arrangement of micro pillars on the basic flow patterns and heat and mass transport. Several important discoveries have been made: 1) regularly arranged surface structures accumulate small deviations of fluid trajectories caused by fluid inertia and create a spiral long-range advection, 2) long-range advection couples with local advection in micro eddies among the micro pillars to form coupled transport mechanisms, 3) local and long-range advection have different dependences on the streamwise and spanwise distances between micro pillars, leading to different transport efficiencies. The phenomena are analyzed in depth.