10 



CROSS FLOW OSCILLATIONS 





SYMBOL Y/D 



CYLINDER SURFACE CONDITION 



* 0.5 



SAND-ROUGHENED, K/D = 1/100 



X 0.5 



SMOOTH 



0.25 



SMOOTH 



+ 0.5 



SMOOTH 



A 0.25 



SMOOTH 



0.13 



+ 



SMOOTH 



o 



o >.^ 



+ *>. 







ROUGH CYLINDER 





-♦ * ♦__ 



1 1 1 1 1 > 





2- 



12 3 4 5 6 7 8 



REDUCED VELOCITY, V^ = -p- 

 fpD 



Figure 2.20 Total unsteady transverse force coefficient at the locked-on vibration frequency (Force/ I/2/p V^DL). Cjj^^x^ meas- 

 ured on smooth and rough circular cylinders vibrating in the cross flow direction, plotted against the reduced velocity K,; from 

 Sarpkaya (20). The measurements were made under the same conditions as in Fig. 2.3 through 2.6, and lock-on occurs near V^ 



= 5. 



45 



