, nthank you it worked using the modal acoustic analysis system. nI get the damped frequency in the solution. ni have another question though - When you do 'free free modal analysis' using modal analysis system . for the first 6 modes the natural frequency is 0. nwhy aren't the first 6 frequencies not 0, when i do free free modal analysis of submerged structures using Modal Acoustic analysis system? nis it a sign that I am doing something wrong ?.Regards nUmang n