Transient behaviors of mixed convection in a square enclosure with an inner impulsively rotating circular cylinder

摘要: Abstract This work numerically investigated the unsteady mixed convective heat transfer between a square enclosure and an inner concentric circular cylinder maintained at different temperatures. The undergoes transition of motion whose physics is significant for engineering applications such as cooling rotating shaft lubricating journal bearing. It keeps stationary first steady-state natural flow achieved, then impulsively rotates constant angular velocity arrives new final steady-state. Although configurations are analyzed in number works, transient behaviors thermal characteristics from onset rotation to not investigated, which restrains thorough understandings on relevant mechanisms. present performs numerical investigation targeted physical problem. objective explore transfer, identify effects speed (tangential surface, V0) behaviors. results presented by temporal variations spatial distributions field, mean rate, local rate velocity/temperature certain regions where significantly affected. Our time two regimes depending tangential velocity: buoyancy-shear stress dominated V0 ≤ 1.0 effect convection pronounced driven both buoyancy shear V0 ≥ 2.0 almost entirely realized conduction. quantities characterized categorized based regimes.