Figure 9. Calibration tests for mode 

 1-1-1, showing attenuation coefficient 

 (a ) vs. distance (D) between free sur- 

 face and cavity sill, using pure water 

 at four different temperatures as in- 

 dicated. 



Figure 10. Calibration tests for mode 

 1-1-1, showing attenuation coefficient 

 of figure 9 replotted vs. the resonant 

 frequency (f ). 



67 



