Abstract: The vibroacoustical characteristics of a double shell-fluid system,which consists.of two infinite concentric cylindrical elastic thin steel shells (hereafter referred to as a double shell simply) coupled by the entrained axial uniform water flow,is investigated.Using a fully coupled model between fluid and shells,the dispersion behaviour is analysed for the system,vibrating in the n=0 and n=1 circumferential modes.The impact of the flow on the dispersion curves is also discussed for the system.