obtained with yawed and unyawed flexible cantilevered cylinders that underwent cross flow oscillations 

 in flowing water of various depths (in relation to the cylinder's length). 



Table 2.2. Vortex-excited cross flow displacement amplitude 

 response of cylindrical structures. 

 Legend for Data Points in Fig. 2.2 



Type of cross-section and mounting; medium 



Symbol 



Various investigators, from Griffin (6): 





Spring-mounted rigid cylinder; air 



*OHMe 



Spring-mounted rigid cylinder; water 



♦ 



Cantilevered flexible circular cylinder; air 

 Cantilevered flexible circular cylinder; water 



A 



Xv© 



Pivoted rigid circular rod; air 



DA 



Pivoted rigid circular rod; water 



• 



From Dean, Milligan and Wootton (5): 





Spring-mounted rigid cylinder; water 

 Flexible circular cylinder, L/D = 240; water 



a 



From King (16): 





Cantilevered flexible circular 

 cylinder, LiD = 52 (PVC); water 



© 



Cantilevered flexible circular 



cylinder, L/D = 52 (Stainless steel); water 



9 



2.2 Hydrodynamic Forces. The unsteady fluid dynamic forces acting on a resonantly vibrating, 

 cylindrical structure due to vortex shedding have been categorized as follows (4,6): 



• The exciting force, by which energy is transferred to the structure and which drives the vibra- 



tions; 



• The reaction or damping force, which is exactly out-of-phase with the structure's velocity; 



• The "added mass" force, which is exactly out-of-phase with the structure's acceleration; 



The fluid inertia force. 



