In a hydroelectric power plant or in a pumping station in order to avoid sudden large increase of pressure due to instantaneous valve closure sometimes a surge tank is installed. The height of surge tank is designed by the highest possible water level during the operation. The theoretical treatment of oscillation in a surge tank is difficult because of the non-linearity of friction term in the ...

An experimental study was performed to identify the surge inception dynamics and to demonstrate an active surge control on a 600 HP class Allison 250-C30 gas turbine engine. Throttling orifices inserted between the compressor and the combustor were used to move the steady state operating line toward the surge line. The compressor was then adjustably throttled into surge using water injection do...

To avoid co-surge the mass flows should be kept balanced. Still co-surge can occur when operating close to the surge line due to disturbances between the two mass flows. In that case the control system needs to detect the co-surge oscillation and take proper actions. The simulation model is used to evaluate detection and control algorithms, which are then tested in vehicle. −0.25 0 0.25 0.5 0.7...

With liberalization of European market, many high head power plants in Switzerland increase their potential generation to remain competitive. The existing surge tanks have to be modified to keep the flow management constant. A relevant way to limit the time of mass oscillation is to increase head losses at the entrance of a surge tank with an orifice. This study focuses on the influencing param...

Studies of center of mass (COM) motion are fundamental to understanding the dynamics of animal movement, and have been carried out extensively for terrestrial and aerial locomotion. But despite a large amount of literature describing different body movement patterns in fishes, analyses of how the center of mass moves during undulatory propulsion are not available. These data would be valuable f...

This paper describes the phenomena of glacier surges and presents a mathematical model based on realistic descriptions of glacier physics, which purports to describe the main features of the flow. The analysis reveals and predicts a variety of phenomena, many of which have been observed to occur, and gives explicit estimates for such quantities as surge front extent, "mini-surge" propagation sp...

this work studies the effect of neutral earth resistance on the controlling ferroresonance oscillation in the power transformer including MOV surge arrester. A simple case of ferroresonance circuit in a three phase transformer is used to show this phenomenon and the three-phase transformer core structures including nonlinear core losses are discussed. The effect of MOV surge arrester and neutra...

The characteristics of seasons with enhanced East Coast winter storm and storm surge activity are identified from among a set of global atmospheric circulation indices and local land and sea surface temperature anomalies. Without regard for storm strength or surge potential, the most active East Coast winter storm (ECWS) seasons occur in association with El Niño events. There is also some indic...

surge and rotating stall phenomena are two dynamic instabilities that occur in both axial and centrifugal compressors. surge is the stream instability phenomenon in compressor that imposes severe damages to the compressors. nowadays, suppressing surge phenomenon is one of the most important issues in oil and gas industries, especially when flow reduction or gas reflux is considered. this resear...