property of the turbulence in the thick axisymmetric stern boundary layer. 

 The present set of experimental results is consistent with the conjecture 

 of Townsend that the flow patterns in a wake and in a boundary layer 

 possess an overall structural similarity. It may not be necessary to use 



"local" equations for turbulent Reynolds stresses with a diffusion term 



9 

 and with a correction to the extra rate of strain. 



CONCLUSIONS 

 The present investigation of the thick axisymmetric turbulent 



boundary layer on an inflected stern without shoulder separation is an 



1 2 

 extension of the earlier research reported by Huang et al. ' An 



additional comprehensive set of boundary layer measurements, including 



mean and turbulence velocity profiles, turbulence Reynolds stresses, static 



pressure distribution, and correlation length scales of the turbulence, are 



presented. The following major conclusions can be drawn. 



7 8 



The Preston and Lighthill displacement body concept has further been 



proven experimentally to be an efficient and accurate approach for computing 



the viscid and inviscid stern flow interaction on axisymmetric bodies. 



The measured static pressure distributions on the body and across the 



entire thick boundary layer were predicted by the displacement body method 



to an accuracy within one percent of dynamic pressure. 



Neither the measured values of eddy viscosity nor the mixing length 



were found to be proportional to the local displacement thickness or the 



local boundary-layer thickness of the thick axisymmetric boundary layer. 



The measured mixing length of the thick axisymmetric stern boundary layer 



was again found to be proportional to the square root of the area of the 



turbulent annulus between the body surface and the edge of the boundary 



layer. This simple similarity hypothesis for the mixing length and the 



displacement body concept have been incorporated into the Douglas C-S 



5 3 



differential boundary-layer method by Wang and Huang. The improved 



method predicts satisfactorily the measured mean velocity distributions in 



the entire stern boundary layer. 



The measured correlation length scales of the turbulence and the 



measured Taylor microscales in the entire stern boundary layer are found to 



48 



