Turbulence intensity 



Two sets of data are analyzed in some detail at this stage: (a) tests of 

 3-sec wave conditions with H = 0.2 (S0314B), 0.6 (S0315A), and 0.8 m 

 (S0414), and (b) tests of 8-sec wave conditions with H = 0.4 (S0410A), 0.5 

 (combined S0609A, S0610A, S0612A, S0614A), and 0.7 m (S0409B). An 

 example of the phase distribution of the root-mean-square (rms) turbulence 

 intensity «'„„, is shown as the symbol + in Figure 11-6. The distribution 

 appears to contain harmonics, suggesting the presence of nonlinear processes. 



The vertical distribution of turbulence intensity averaged over the complete 

 wave cycle is presented in Figure ll-7a. The profiles under the 3-sec wave 

 conditions with wave height 0.2 (o, Run S0314B), 0.6 (x, Run S0315A), and 

 0.8 m (+, Run S0414A) are shown with solid lines. The nearly constant but 

 low turbulence intensity of Run S0314B reflects ambient conditions in the 

 water column when wave motion is rather mild. With more vigorous 



10 2 



: (a) 



101 



10° 



-i i i i i 1 1 



10' 



102 



101 



10° 



-I — I — I I I 1 1 



(b) 



101 101 



u' (cm/sec) 



Figure 1 1-7. Vertical distribution of (a) turbulence intensity u' ms (cm/sec) and (b) sediment 

 concentration, in the lowest 1 6 cm on water column 



Chapter 1 1 LDV in the Bottom Boundary Layer 



225 



