The water depth was veil over 2,000 feet. The 

 wave records indicate that the sensors did not 

 follow the downward motion of the buoy as 

 accurately as they did the upward motion. 



For this experimental setup the output of the 

 pressure transducers was recorded on strip 

 recorders rather than feeding into the electrical 

 calorimeter as would be done for telemetering. 

 Digital data taken from the 2 gages in the array 

 were subsequently processed to obtain a power 

 spectrum of the energy as measured at the par- 

 ticular depth of each gage (not corrected for 

 depth). The areas under each of the plots of 

 these spectra (as shown in Fig. 5) are equal 

 and the respective normalizing factors required 

 to reduce the area to the particular value are 

 shown. Since the area under a non-normalized 

 plot would be proportional to the total energy, 

 the normalizing factor is proportional to the 

 energy and would therefore be directly related 

 to the rise in temperature which would occur in 

 the electrical calorimeter. The ratio of the 



normalizing factors is 5-8. The single wave 

 period which would give this particular ratio for 

 two gages at the depth used is about 23 seconds. 

 The actual spectra have maxima around 10 seconds, 

 thus giving a rather large discrepancy. These 

 preliminary tests have pointed up a number of 

 changes which must be made in the experimental 

 setup for future experiments to evaluate the 

 overall feasibility of this approach to sea-state 

 measurement . 



REFERENCES 



1. VON WALD, W. A. Jr. and J. E. DINGER, The 

 electrical calorimeter as an integrating 

 device, Rept. 5796, U. S. Naval Research 

 Laboratory, July I962. UNPUBLISHED. 



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Fig. 5- Energy spectra from suspended wave sensors. 



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