A synthetic jet cooling device (1) for cooling an object (5), comprising: a transducer (10) adapted to generate velocity waves, and an enclosure (4) arranged to receive the velocity waves via an actuated aperture (8). The enclosure (4) is sufficiently large to generate, at the actuated aperture (8), an internal synthetic jet inside the enclosure (4). Furthermore, the enclosure (4) is arranged to contain the object (5), thereby enabling cooling of the object (5) by the internal synthetic jet. The arrangement typically permits multifunctional use of an existing enclosure, containing the object to be cooled, both for its original purpose (e.g. a reflector in a lamp, or a LED backlight module) and as an enclosure generating internal synthetic jets, why the cooling device typically requires virtually no extra space and weight, and can be provided at a low cost.