Foil bearings are an integral part of oil-free turbomachines which have been selected as a potential technology to enable cost efficient Supercritical Carbon Dioxide Brayton cycle for solar power application. Using high pressure CO2 as the operating fluid means that within the film Reynolds numbers in the highly turbulent regime are observed, therefore, using traditional simulation tools, such ...

The augmented complex Kalman filter (ACKF) has been recently proposed for the modeling of noncircular complexvalued signals for which widely linear modelling is more suitable than a strictly linear model. This has been achieved in the context of neural network training, however, the extent to which the ACKF outperforms the conventional complex Kalman filter (CCKF) in standard adaptive filtering...

Spiral waves rotate either around a circular core or meander, inscribing a noncircular pattern. The medium properties determining the transition of meandering were found to be equivalent to those defining the transition from wave tip separation and attachment around the end of an unexcitable strip of thickness comparable to zero velocity wave-front thickness. The transition from circular to non...

Observational evidence for dynamo action in spiral galaxies is reviewed, and the capabilities of various theories in explaining the basic features of galactic magnetic fields are discussed. Mean-field dynamo models appear to be unique in providing a coherent explanation of a wide variety of magnetic features in spiral galaxies. Reliable modelling of global magnetic structures, such as the magne...

In this paper, the effectiveness of stiffness and damping of bearing is investigated on the natural frequencies of the rotor-bearing system. The rotor-bearing system consists of a shaft, two bearings and a disk between two bearings. Parallel spring-damper in horizental and vertical directions is considered for modeling the stiffness and damping of bearings. The gyroscopic effect is also conside...

Antti Kärkkäinen Dynamic Simulations of Rotors during Drop on Retainer Bearings Lappeenranta, 2007 91 p. Acta Universitatis Lappeenrantaensis 279 Diss. Lappeenranta University of Technology ISBN 978-952-214-444-7; ISBN 978-952-214-445-4 (PDF) ISSN 1456-4491 The active magnetic bearings have recently been intensively developed because of noncontact support having several advantages compared to c...