An eight-by-eight jet array impinging onto a staggered array of dimples at Reynolds number 11,500 was investigated by the transient wide band liquid crystal method. The distance between the perforated plate and the target plate was adjusted to be 2, 4 and 8 jet diameters to examine its effect on the heat transfer performance. Two dimple geometries of hemispherical and cusped elliptical were examined. Moreover, the effect of crossflow scheme on heat transfer was investigated: one-way, two-way and four-way spent air exits. All heat transfer results were normalized by those from a flat surface at the same condition. (C) 2004 Elsevier Ltd. All rights reserved.