Full scale monitoring of the twin chimneys of the rovinari power plant

Abstract

Abstract. The presented paper deals with the structural identification and monitoring of two twin chimneys in very close arrangement. Due to twin arrangement, important interference effects are expected to modify the chimney response to wind action, causing vortex shedding and state-dependent excitation associated to the oscillatory motion of the leeward chimney, in and out of the windward chimney wake. The complexity of the physics of this problem is increased by the dependency of the aerodynamics of circular cylinders on Reynolds number; however, there is a weakness of literature about cylinders behaviour at critical and super-critical range of Reynolds number, due to experimental limitations. Also the International Committee on Industrial Chimneys (CICIND) does not provide, at present, any specific technical guideline about twin chimneys whose interaxis distance is less or equal two times the diameter, as in this case. For this reason a Tuned Mass Damper (TMD) has been installed in order to increase the damping of the chimney, as merely suggested. This work aims at assessing the effectiveness of the installed TMD and characterizing the tower dynamic behaviour itself due to the wind excitation, as well as providing full scale measurements for twin cylinders configuration at high Reynolds numbers.

Modal parameters identification and monitoring of two arches

“…All the instrumentation signals were stored by devices provided by a processor and able to acquire and process the data in stand-alone mode [12]. The acquisition system was configured in order to acquire data for 10 minutes, to produce synthetic information for each channel (mean value, standard deviation, peak value) and to store them.…”

“…For these reasons, tests on the real structure can be required to characterize it in terms of its modal parameters before and after the TMD installation [6,7,8]. Thanks to the advance in the stand-alone acquisition systems, it is also possible to easily check the structure behaviour during a wide time-window [9,10,11,12].…”