This work presents and discusses the results of an experimental investigation of the heat transfer between the constant-heat-flux test plate and the impinging jets. The round jets with/without swirling inserts are used. Smoke flow visualization is also used to investigate the behavior of the complicated flow phenomena under the swirling-flow jet for this impingement cooling. The effects of flow Reynolds numbers (500less than or equal toReless than or equal to27 000), the geometry of the nozzle (BR, LSS and CSS), and jet-to-test plate placement (3less than or equal toH/dless than or equal to16) are examined. (C) 2003 Elsevier Ltd. All rights reserved.