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DISCUSSION 



K. Wieghardt 

 J Institut fur Schiffbau der Universitdt Hamburg 

 Hamburg, Germany 



Experimentally the same critical Reynolds number has been found for water 

 and air. Are you sure that your theory would also give critical Reynolds num- 

 bers independent of the speed of sound if no experimental data were used ? 



REPLY TO DISCUSSION 



A. S. Iberall 



Yes. In fact one of the self-consistent and thereby validating facets of this 

 theory is that the compressibility relation involving water leads to the same re- 

 sults for air. In other words, we are predicting something about how frequency 

 results for air and water are transformed for comparable Reynolds number de- 

 termined turbulent states. 



In the paper, two estimates are made of the critical Reynolds number. One 

 uses no experimental data for the estimate, the other does. 



748 



