Journal of Sound and Vibration (1996) 194(4), 639

COMMENTS ON ‘‘NATURAL MODE ANALYSIS OF HOLLOW ANDANNULAR ELLIPTICAL CYLINDRICAL CAVITIES’’

P. A. A. L, L. E, D. V. B C. A. R

Institute of Applied Mechanics (CONICET)and

Department of Engineering, Universidad Nacional del Sur, 8000—Bahı́a Blanca, Argentina

(Received 28 August 1995)

The authors are to be congratulated for their very extensive and thorough investigation[1]. It is important to point out that a rather limited amount of numerical and graphicalinformation on frequencies and mode shapes on annular, elliptical domains was availablein the open literature and Drs Hong and Kim have accomplished a very valuable serviceto the scientific community.

On the other hand, it is important to point out that very important studies have beenperformed on hollow elliptical waveguides by Kretzschmar [2,3] and by Davies andKretzschmar [4] in electromagnetic waveguide theory. The boundary condition consideredby Hong and Kim [1] corresponds to the case of a transverse electric (TE) field propagatingin a hollow, elliptical waveguide.

1. K. H and J. K 1995 Journal of Sound and Vibration 183, 327–351. Natural mode analysisof hollow and annular elliptical cylindrical cavities.

2. J. G. K 1970 IEEE Transactions on Microwave Theory and Techniques 18, 547–554.Wave propagation in hollow conducting elliptical waveguides.

3. J. G. K 1972 IEEE Transactions on Microwave Theory and Techniques 20, 280–284.Attenuation characteristics of hollow conducting elliptical waveguides.

4. J. B. D and J. G. K 1972 Proceedings of the IEE 119, 519–522. Analysis ofhollow elliptical waveguides by polygon approximation.

639

0022–460X/96/290639+01 $18.00/0 7 1996 Academic Press Limited