Near-wall roughness for damping devices reducing pressure oscillations in combustion systems

A damping device for reducing pressure oscillations in a combustion system (1) according to the invention comprises at least a portion (9) provided with a first, outer wall (11), a second, inner wall (12), an intermediate plate (16) interposed between the first wall (11) and the second wall (12), wherein this intermediate plate (16) forms a spacer grid to define at least one chamber (17) between said first wall (11) and said second wall (12), first passages (14) connecting each of said at least one chamber (17) to the inner of the combustion system (1), and second passages (15) connecting each of said at least one chamber (17) to the outer of the combustion system (19), wherein the second passages (15) open at the same side of said chambers (17) as the first passages (14), the second passages (15) have a portion extending parallel to the inner wall (12), and wherein this parallel portion of said second passages (15) is equipped with heat transfer enhancing means (20, 21).