Measurements are made of vortex-induced vibration of an elastically supported circular cylinder in water with reduced velocity (U/fnD) from 2 to 12, damping factors from 0.2% to 20% of critical damping, mass ratios (m/ρD2) from 2.8 to 17, and transverse, inline, and combined inline and transverse motions with up to 1.49 diameters amplitude. Effects of mass ratio, damping, and strakes are investigated.
It is well known that vortices are periodically shed by a cylinder in a cross flow. Vortex shedding induces vibration of elastic cylinders and cylinder motion affects the shedding process. Ten reviews of vortexinduced forces and vortex-induced vibration are Gabbai and Benaroya (2005), Williamson and Govardhan (2004), Norberg (2003), Sarpkaya (1979, 2004), Khalak and Williamson (1999), Griffin and Hall (1991), Blevins (1990), Bearman (1984), King (1977), and Leinhard (1966). Recent experimental papers include Jeon and Gharib (2004), Flemming and Williamson (2005), Dahl, Hover, and Triantafyllou (2006), Laneville (2006), Klamo (2006), Dipankar, Sengupta and Talla, (2007), Carberry and Sheridan (2007), Prasanth and Mittal (2008). A test program of vortex-induced vibration of elastically supported circular cylinders was made with reduced velocity (U/fnD) from 2 to 12, damping factors from 0.2 to 20%, mass ratios from 2.8 to 17 and transverse, inline, and combined inline and transverse motion.
Tests were conducted on an aluminum cylinder with 2.5 inch (6.35 cm) outside diameter in the stratified flow channel at the Scripps Institution of Oceanography. Its surface was sanded with 220 grit sand paper to give a average roughness of approximately 30 micro inch (Ra) roughness, k/D = 10 x10−5. The cylinder pierces the water surface and extends 44.3 inch (1.125 m) into the flow, ending 2 mm (0.08 inch) above the channel bottom.