polynomial was used to determine the boundary layer flow. The coefficients 

 for this polynomial were determined by the conditions that the thickness, 

 slope, and curvature be equal to those calculated by the modified boundary- 

 layer method at x/L = 0.95 and by the Granville integral wake relations at 

 x/L = 1.05. This method was found by Huang et al. to give excellent 

 agreement with experimental values of pressure, shear stress, and velocity 

 profiles over the forward 90 percent of the bodies investigated. As the 

 boundary-layer thicknesses became larger, particularly when these thick- 

 nesses became greater than the radii of the bodies, the measured values of 

 shear stress and velocity became smaller than those predicted by the 

 theory. 



In the following discussion, the experimental techniques and 

 geometries of the model are given in detail. The experimental and theo- 

 retical results are compared and the measured turbulence characteristics 

 are presented. The method of obtaining the eddy viscosity and mixing 

 length is discussed and the experimentally-determined distributions are 

 given. The concept of similarity length-scale in the thick stern boundary 

 layer is examined experimentally. The square root of the annular area be- 

 tween the body surface and the edge of the boundary layer is found to be 

 the appropriate length scale for the axisymmetric thick stern boundary 

 layer . 



WIND TUNNEL AND MODEL 



The experimental investigation was conducted in the DTNSRDC anechoic 



wind tunnel facility. The wind tunnel has a closed jet test section that 



is 8 ft (2.4 m) square and 13.75 ft (4.19 m) long. The corners have 



fillets which are carried through the contraction. The test section is 



followed by an acoustically-lined large chamber 23.5 ft (7.16 m) long. It 



was found previously by Huang et al., that the ambient free-stream 



/— 2 

 turbulence levels, (/ u' /U ) x 100, are 0.075, 0.090, 0.100, and from 



0.12 to 0.15 for free-stream velocities U of 24.4, 30.5, 38.1, and 45.7 



m/s, respectively. Integration of the measured noise spectrum levels in 



the test section from 10 to 10,000 Hz indicated that the typical background 



