- Volume 25 Issue 8
This paper deals with the dispersion relation of the waves sustained in a cylindrical shell submerged in the fluid. The waveguide finite method and the boundary element method are used to predict the dispersion characteristic of the cylindrical shell. The dispersion diagram of the cylinder is estimated from the eigenvalue problem and the forced vibration response. It follows that the water-loading leads to the decrease of the cut-on frequencies and the phase speeds of the bending waves. On the contrary, the longitudinal waves and the torsional waves are hardly affected by the fluid, and therefore the order of the cut-on frequencies of the waves is changed. The acoustic dispersion diagram is also estimated from the forced acoustic response to identify the characteristics of the wave radiated to the fluid. It follows that the acoustic waves on and near the surface of the cylinder are the same as those in the structure. But at the far field the acoustic waves caused by subsonic waves e.g., the bending waves disappear as the increase of the distance. Conclusively, the characteristics of waves in cylindrical shells are significantly affected by water-loading in terms of the cut-on frequency, the wave speed, the order of the cut-on and radiation.
분산선도;원통형 실린더;파동;도파관 유한요소법;파수경계요소법
- Han, S. J., Lee, J. J. and Kang, M. H., 2014, Prediction of Total Acoustic Radiation Power of the Submerged Circular Cylindrical Structures, Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 24, No. 11, pp. 876~882. https://doi.org/10.5050/KSNVE.2014.24.11.876
- Sohn, J. W., Kwon, O. C. and Choi, S. B., 2009, Modal Characteristics and Vibration Control of Cylindrical Shell Structure : Experimental Results Comparison in the Air and Water, Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 19, No. 9, pp. 899~906. https://doi.org/10.5050/KSNVN.2009.19.9.899
- Nilsson, C. M. and Finnveden, S., 2008, Waves in Thin Walled Fluid-filled Ducts with Arbitrary Cross-sections, Journal of Sound and Vibration, Vol. 310, No. 1, pp. 58~76. https://doi.org/10.1016/j.jsv.2007.07.081
- Park, Y. J., Kim, S. J., Han, K. H. and Lee, Y. S., 2003, A Study on the Modal Characteristics of Submerged Cylindrical Shell, Transactions of the Korean Society for Noise and Vibration Engineering, pp. 284~285.
- Ryue, J., Thompson, D. and White, P. R., 2007, Wave Propagation in Railway Tracks at High Frequencies, Proceedings of the 9th International Workshop on Railway Noise, Munich, Germany, pp. 440~446.
- Ryue, J., 2010, A Numerical Method for Analysis of the Sound and Vibration of Waveguides Coupled with External Fluid, The Acoustic Society of Korea, Vol. 29, No. 7, pp. 448~457.
- Nilsson, C. M., Jones, C., Thompson, D. and Ryue, J., 2009, A Waveguide Finite Element and Boundary Element Approach to Calculating the Sound Radiated by Railway and Tram Rails, Journal of Sound and Vibration, Vol. 321, No. 3-5, pp. 813~836. https://doi.org/10.1016/j.jsv.2008.10.027
- Finnveden, S. and Nilsson, C. M., 2007, Input Power to Waveguides Calculated by a Finite Element Method, Journal of Sound and Vibration, Vol. 305, No. 4, pp. 641~658. https://doi.org/10.1016/j.jsv.2007.04.025
연구 과제번호 : 첨단 기계부품소재 인력양성사업단