Air-Sea Interaations ; Program at IMST 



1, Overall Aerodynamic Tests 



The first use of the model has been to test the global aero- 

 dynamic performance of the facility. The initial design, represented 

 by the upper part of Fig. 11, suffered from several imperfections 

 resulting in a low power factor and in an inadequate working stability. 

 Detailed flow explorations have led to successive amendments in the 

 geometry of the model (see Pouchain [ 1970] and Coantic et al. [1969]) 

 The final design, shown in the lower part of Fig. 11, offers~satis- 

 factory performance, and has therefore been adopted in the later 

 building of the large facility, the aerodynamic characteristics of 

 Axhich have been predicted from the model tests. 



SECTION A 



SECTION B . C 



INITIAL 

 SECTION D 



E^ 



1m 



SECTION E.F 



P7-T 



FINAL 



Fig. 11. Improvements in aerodynamic design of the model 



2. Flow Exploration and Improvement in the Working Section 



A deeper flow study of the working section has then been per- 

 formed, of which typical results, obtained for a wind velocity of 

 8.3 m/s, are displayed by Fig. 12. It can be seen that the situation 

 is good in the entrance section, with a very flat velocity profile, 

 and a turbulence intensity below 0.002 (the effects that can be dis- 

 cerned near the water surface are the consequence of artificial 

 boundary layer thickening in the final part of the contraction). The 

 further growth of the various boundary layers, and the fact that they 



53 



