Confined impinging air jet at low Reynolds numbers

The flow field between two horizontal surfaces arising from jet issuing from the lower surface and impinging normally on the upper surface have been experimentally investigated for a single jet and double jet. The velocity and pressure distributions in the impingement region were obtained over a Reynolds number range of 300-10 000 and a nozzle-to-plate spacing range of 0.5-4. The effects of Reynolds number and nozzle-to-plate spacing on the flow structure are reported. It is concluded that a subatmospheric region occurs on the impingement plate at nozzle-to-plate spacings up to two for Reynolds numbers greater than 2700 and that there exists a linkage between the subatmospheric region and the peaks in heat transfer coefficients. (C) 1999 Elsevier Science Inc. All rights reserved.