1.0 



0.9 



o 



|> 0.8 



- \ 



- \ 



K 0.7 I— 



uj 0.6 

 o 



< 



- \ 



Si 0-5 



5 0.4 

 o 



^ 0.3 



en 



en 



O 



ct 0.2 



o 



0. I — 



0.0 H/- 



Q>.1 



DA V 



\D 



YAW ANGLE ;8 



LOCK-IN 

 REGION 



0\ A 



X-O" 

 O-20° 



a -30' 



A -40' 

 V- 50' 



/ 



A 

 / ^ 



/ 



°^_^__^ ^o 



0.8 



0.9 



I.I 



1.3 



VIBRATION /STROUHAL FREQUENCY RATIO, f/fg 



Figure 2.19 Lock-on boundaries (in terms of the cross flow displacement amplitude 2Yl D) plotted against tlie ratio of 

 vibration and Strouhal frequencies; from Ramberg (28). The Strouhal frequency /j was estimated from the cosine law 

 relation /j = 0.21 K cos /3/D. Z,oc/c-on occurs inside the area bounded by the data points and dashed lines, and the 

 latter correspond to the case of flow normal to the vibrating cylinder. 



44 



