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Power resource estimate of ocean surface waves
Ocean Engng. Vol. 4, p. 213. Pergamon Press 1977. Printed in Great Britain
POWER RESOURCE ESTIMATE OF OCEAN SURFACE WAVES* Closure NARAYANA N. PANICKER Mobil Research and Development Corporation P.O. Box 900, Dallas, Texas 75221, U.S.A. The author thanks Ivar G. Jonsson for his valuable discussion of the paper. The writer is to be congratulated for pointing out "a misunderstanding which apparently is not too easy to remove from the coastal engineering literature" and discussing it in great detail. The fact that the area under the spectrum represents the total energy and not just the potential energy needs to be emphasized to neutralize the statements to the comrary on page 433. The author erred in using significant wave height instead of root mean square wave height in calculating wave energy and power with the equations derived in the paper. As the square of the significant wave height is twice the square of the r.m.s, wave height for a fairly narrow spectrum, the energy and power calculated in Section 2.2 of the paper are too large by a factor of 2. Hence the total wave energy of the world oceans is 800 x 10 a5J and total wave power is 45 x 1015 W for 12Z October 2, 1975. However, referring to the discussion on page 437 on the accuracy of these computations, we may see that the objective of estimating the order of magnitude is unscathed by this, nevertheless, regrettable mistake. The author compliments the writer for his thoughts on the concept of wave power, which are shared by the author as evidenced in the derivations in Section 2.1. However, in discussing a renewable power source such as waves, the use of the term total wave power is advantageous. The writer himself has given an interpretation to the meaning of total wave power, which is uniquely related to total wave energy. But his contention that the sea would be calm once power is extracted does not recognize the renewable nature of wave power and the renewal rate estimated elsewhere in the paper. With regards to the final comment of the writer, the author agrees with him that a more consistent assumption o f deep water conditions would result in halving the author's estimate of wave energy dissipation rate along the coastlines of the world to 2.6 × 10TM W. This is very close to the figures of Kinsman (2.2 × 10TM W) and Inman and Brush or Isaacs and Seymour (2.5 × 10TM W). Such a close agreement is surprisingly good indeed. In summary, the wave energy and power computed in the paper from wave climatological data may be too large by a factor of two and this statement may be treated as a corrigendum to the paper. A typing error also needs correction in the term sin h Kd in equation (2.4) which should read sinh 2kd.
*Ocean Engineering, Vol. 3, pp. 429-439 by Narayana N. Panicker. 213
POWER RESOURCE ESTIMATE OF OCEAN SURFACE WAVES* Closure NARAYANA N. PANICKER Mobil Research and Development Corporation P.O. Box 900, Dallas, Texas 75221, U.S.A. The author thanks Ivar G. Jonsson for his valuable discussion of the paper. The writer is to be congratulated for pointing out "a misunderstanding which apparently is not too easy to remove from the coastal engineering literature" and discussing it in great detail. The fact that the area under the spectrum represents the total energy and not just the potential energy needs to be emphasized to neutralize the statements to the comrary on page 433. The author erred in using significant wave height instead of root mean square wave height in calculating wave energy and power with the equations derived in the paper. As the square of the significant wave height is twice the square of the r.m.s, wave height for a fairly narrow spectrum, the energy and power calculated in Section 2.2 of the paper are too large by a factor of 2. Hence the total wave energy of the world oceans is 800 x 10 a5J and total wave power is 45 x 1015 W for 12Z October 2, 1975. However, referring to the discussion on page 437 on the accuracy of these computations, we may see that the objective of estimating the order of magnitude is unscathed by this, nevertheless, regrettable mistake. The author compliments the writer for his thoughts on the concept of wave power, which are shared by the author as evidenced in the derivations in Section 2.1. However, in discussing a renewable power source such as waves, the use of the term total wave power is advantageous. The writer himself has given an interpretation to the meaning of total wave power, which is uniquely related to total wave energy. But his contention that the sea would be calm once power is extracted does not recognize the renewable nature of wave power and the renewal rate estimated elsewhere in the paper. With regards to the final comment of the writer, the author agrees with him that a more consistent assumption o f deep water conditions would result in halving the author's estimate of wave energy dissipation rate along the coastlines of the world to 2.6 × 10TM W. This is very close to the figures of Kinsman (2.2 × 10TM W) and Inman and Brush or Isaacs and Seymour (2.5 × 10TM W). Such a close agreement is surprisingly good indeed. In summary, the wave energy and power computed in the paper from wave climatological data may be too large by a factor of two and this statement may be treated as a corrigendum to the paper. A typing error also needs correction in the term sin h Kd in equation (2.4) which should read sinh 2kd.
*Ocean Engineering, Vol. 3, pp. 429-439 by Narayana N. Panicker. 213