C,6 • KINEMATICS OF TURBULENCE 



10 

 8 

 6 

 4 

 2 



2 



r, cm 



0.05 



-0.04 



0.03 



-0.02 



-0.01 



2 4 6 8 



r/cm 



Fig. C,6c. Top, double correlation functions involving velocity and temperature 

 fluctuations u and d behind a heated grid set perpendicular to a uniform air stream. 



_ g(a:)e(3: + r) 

 ^^^' ~ 0'{x)e'{x + r) 



u{x)u{x + r) 



u'{x)u'{:x + r) 



where x and r denote distance in the direction of the stream and a dash indicates the 

 root mean square value. M is the mesh width of the grid (after Kistler, O'Brien, and 

 Corrsin [18]). 



Bottom, triple correlation functions obtained by the same authors under the same 

 conditions as those in Fig. C,6c, top. 



, , , u'^{x)u{x + r) 

 u^(x)u {x + r) 



., u{x)e{x)6{x + r) 



Vyr) = — 



u'{x)e'(x)e'(x + r) 



{ 207 ) 



