Abstract: The grooves on the wall of the pipeline have impacts on the internal flows, such as inducing vibration and noise. In engineering devices, the grooves on the walls are very common in duct systems. In the case of repeated grooves, each groove can be a source of noise, and the noises from different grooves can interfere with each other. If the grooves are reasonably placed, the flow interference between the grooves may occur, which is possible to weaken the overall noise level. In this paper, the two-dimensional flows and their radiated aeroacoustic sounds in the cavity problems are calculated using direct numerical simulation (DNS). A planar single cavity and four cases with opposed double cavities with different staggered distances are studied. Then, the obtained aeroacoustic behavior and acoustic power are calculated. Effects of the staggered distance on the interference between cavities are analyzed. The results show that the double cavities in the pipe can cut down the overall noise level. The staggered distance has a direct influence on the phase of the flow oscillation, which may reduce the amplitudes of the sound waves. The pipe noises in both upstream and downstream of the cavities are reduced at the same time. Because of the directivity of acoustic propagation, changing the space between the two cavities may result in different noise reductions in both upstream and downstream positions. Comparison between cases shows that the best noise reduction in the upstream of the cavity at the staggered distance is around half cavity-depth. However, for the downstream the best noise reduction takes place when the staggered distance is equal to the cavity-depth.The best overall noise reduction occurs at the staggered distance of around half cavity-depth.