Y(cm) 



4> '180' 



200 300 



Fig. 3. Turbulent shear stresses vs. 



height ( model result, 



A JC's result). 



15 



Y (cm) 



\ 



r ■ A. RAP Model 



I — - Experimeniol 



\ ■ — Gront a Modsen's Model 



0.1 02 0.3 0.4 



Phase Log in Rodions 



0.5 



Fig. 4, 



Fig. 5. 



.5 I 1.5 2 



Ttfnt / T^ovg 



Vertical profile of phase 

 lag between mean velocities 

 and free stream velocity. 



Computed log-layer thickness 

 as a function of time over 

 two wave cycles. 



two wave cycles as computed by our model. The log-layer attains its 

 peak thickness of approximately 25 Z^ shortly after the free-stream 

 velocity reaches the peak amplitude, and almost completely diminishes 

 shortly before the free-stream' velocity reaches zero. This is 

 consistent with the velocity profiles shown in Figure 2. For this 

 analysis, the log-layer thickness is defined as the layer within which 

 the turbulent kinetic energy is 95X or more of its wall value. If one 

 defines a log-layer thickness based on the profile of uw, then the 

 thickness is slightly increased. 



240 



