In a systematic experimental study the behaviour of a periodically precessing jet is compared to that or the corresponding steady inline jet. The precessing motion is that of self-sustained unsteadiness which is a consequence of an axisymmetric "Coanda-like" effect. The flow field is characterised by mean flow, turbulence and frequency data from hot wire measurements. Heat transfer data in terms of Nusselt numbers are determined on a specially designed heat transfer plate in the plane of jet impingement. (C) 2003 Elsevier Ltd. All rights reserved.