B,34 • STRUCTURE OF SHEAR TURBULENCE 



For the most part the measured quantities are the velocity fluctu- 

 ations, their mean square values, their time derivatives, space and time 

 correlations, probability distributions, and energy spectra. In a few cases 

 measurements have been made of temperature fluctuations, including 

 correlations, spectra, and velocity-temperature correlations. Due to limi- 

 tations inherent in the hot wire technique, very few measurements have 

 yet been made in the compressible flow range. Low speed boundary layers, 

 jets, and wakes have been the principal objects of investigation. 



Theoretical studies on the turbulent structure of shear flows are not 

 abundant because of the difficult nature of the statistical theories of 

 turbulence and the additional complications arising from anisotropy and 

 inhomogeneity associated with shear flows. Nevertheless, it becomes a 

 lengthy task to present and discuss both the experimental and theoretical 

 sides of the subject. We therefore restrict the present coverage to a listing 

 of references. Qualitative aspects of structure have been discussed in 

 previous articles, and the references there cited will be repeated here 

 only by number. The list covers mainly relatively recent works which 

 are available to us, and it can by no means pretend to be complete. 

 Classification is by subject, each being headed by a brief discussion. 

 Since many works cover topics belonging in different classes, the group- 

 ing must not be considered as rigid. 



B,34. References on Structure of Shear Turbulence. 



General considerations on vorticity and structure of turbulence. The 

 stretching of vorticity and the formation of vortex sheets play an im- 

 portant role in shear turbulence. Studies of these phenomena are gener- 

 ally theoretical, and often have to be based on a simple and isotropic 

 model. 



Agostini, L., and Bass, J. Les theories de la turbulence. Pubis, sci. et tech. Ministere 



air France 237, 1950. 

 Betchov, R. An inequality concerning the production of vorticity in isotropic 



turbulence. J. Fluid Mech. 1, 497-504 (1956). 

 Burgers, J. M. The formation of vortex sheets in a simplified type of turbulent 



motion. Proc. Acad. Sci. Amsterdam 53, 122-133 (1950). 

 Corrsin, S. Hypothesis for skewness of the probability of the lateral velocity fluctua- 

 tions in turbulent flow. J. Aeronaut. Sci. 17, 396-398 (1950). 

 Djang, F. G. A kinetic theory of turbulence. Chinese J. Phys. 7, 176 (1948). 

 Liepmann, H. W. Aspects of the turbulence problem. /. Math, and Phys. 3, 321-342, 



407-426 (1952). 

 Lin, C. C. On Taylor's hypothesis in wind tunnel turbulence. Mem. Nav. Ord. Lab. 



10775, 1950. 

 Lin, C. C. On Taylor's hypothesis and the acceleration terms in the Navier-Stokes 



equations. Nav. Ord. Rept. 2306, 1952. 

 Munk, M. M. A Simplified Theory of Turbulent Fluid Motion. Catholic Univ. of 



America, 1955. 

 Pai, S. I. ViscoiLS Flow Theory. II: Turbulent Flow. Van Nostrand, 1957. 

 Theodorsen, Th. Mechanism of turbulence. Proc. Second Midwestern Conf. Fluid 



Mech., The Ohio State Univ., 1952. 



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