We report some experiments undertaken to investigate the origin of ordered and chaotic laminar vortex streets behind circular cylinders at low Reynolds numbers. We made simultaneous measurements of near wake longitudinal velocity and cylinder lateral vibration amplitude spectra for cylinder Reynolds numbers in the range from 40 to 160. For a non-vibrating cylinder the velocity energy spectra co...

Free-span occurs normally in a pipeline at uneven seabed, dynamic seabed and pipeline crossing. Free spanning in pipeline causes Vortex Induced Vibration (VIV) fatigue, fracture and bursting. In this paper, a pipeline located in South Pars Gas Field is assessed against local buckling and VIV fatigue using probability of failure theory based on the recommended methodology by Det Norske Veritas (...

Large-scale modern wind turbines at standstill are prone to vortex-induced vibrations. In this study, we propose the use of aero-damping map investigate complex vibration responses turbine airfoil 90° attack angle with different levels structural dampings. The amplitude and response frequency in lock-in condition soft conditions agree well contour line on which sum aerodynamic damping is equal ...

Analyzing the vortex-induced vibration of a slender marine structure withlength to diameter ratio up to 200 is the objective of this study. This slender is free to move in both in-line and cross flow directions and immersed completely in water. Three different types of shear currents pass on it and cause to vibrate slender in different forms. Nowadays, these vibrations are very important for de...

As extreme events increase in frequency, flow-disrupting large-scale structures become ever more susceptible to collapse due local scour effects. The objective of this study was validate the functionality passive, flow-excited sensors that can continue operate during an event. sensors, or piezo-rods, feature continuous piezoelectric polymer strips embedded within and along length slender cylind...

Piezoelectric energy harvesters (PEHs) are a kind of harvester that generates electricity due to pressure or vibration. Vortex-induced vibration (VIV) is method utilized wind and bluff body generate the in PEH. The objective this research was study output voltage different bodies with various airflow velocities. Experimental simulation have done study. used PEH consists piezoelectric bimorph re...

in many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. for any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. the failure will happen in the equipment, when this frequency is close to one...