Answer Happy

Answer B & C only
Example 1. (a) Discuss the phenomenon of flow-induced vibration. Explain the different sources of excitation causing; (i) Galloping vibration of structures. (ii) Vortex induced vibration of structures surrounded by a flowing fluid. (b) A vertical suction pipe 3.25 m long with an external diameter of 150 mm is submerged to a depth of 1.25m in a river which flows at 10.8 km/hr as shown below. It is attached to a horizontal pipe as shown. Vortex shedding subjects the system to a moment Mz about the z- axis. This moment is caused by the drag force F. (i) Calculate the magnitude of force F and the moment Mz about the z-axiz. (ii) Calculate the vortex shedding frequency of the submerged pipe. (c) Determine the steady state amplitude of vibration, o, of the suction pipe if the fundamental natural frequency of the system is 3.1 Hz. The torsional spring constant of the pipe is q = 15000 Nm/rad. It is assumed that there is no damping. C= drag coefficient 1.0, p = fluid density = 1000 kg/m3 = The Strouhal number = 0.2 =
2 m Suction pipe 1.25 m (a) (b) Prob. 3-16