Nonstationary Convection in a Rotating System

Author(s):  
F. H. Busse ◽  
R. M. Clever
Keyword(s):  
2021 ◽  
Author(s):  
Alex Moushegian ◽  
Marilyn J. Smith ◽  
Glen R. Whitehouse ◽  
Daniel A. Wachspress

2006 ◽  
Vol 113 ◽  
pp. 213-218 ◽  
Author(s):  
Vytautas Barzdaitis ◽  
Marijonas Bogdevicius ◽  
Rimantas Didžiokas

The article concerns dynamics and vibration of a high power rotating system with toothed wheel coupling that inserts elastic plate packets. Theoretical modeling and simulation of the rotating system with toothed wheel coupling have been provided by a finite element method. Complex model involved a rotating system, hydrodynamic bearings and coupling. The dynamics of semi-couplings and plates have been simulated. Experimental measurement of vibration has been measured with stationary machine condition monitoring and a diagnostic system.


1987 ◽  
Vol 177 ◽  
pp. 381-394 ◽  
Author(s):  
Dominique P. Renouard ◽  
Gabriel Chabert D'Hières ◽  
Xuizhang Zhang

The influence of rotation upon internal solitary waves is studied in a (10 m × 2 m × 0.6 m) channel located on the large rotating platform at Grenoble University. We observe an intumescence which moves along the right-hand side of the channel with respect to its direction of propagation. Along the side, once the intumescence reaches its equilibrium shape, the height variation of the interface with time is correctly described by the sech2 function, and the characteristic KdV scaling law linking the maximum amplitude and the wavelength along the side is fulfilled. The intumescence is a stable phenomenon which moves as a whole without deformation apart from the viscous damping. For identical experimental conditions, the amplitude of the intumescence along the side increases with increasing Coriolis parameter, and at a given period of rotation of the platform, the celerity along the side increases with increasing amplitude. But for identical conditions, we found that the celerity along the side is equal to the celerity that the wave would have for such conditions without rotation. The amplitude of the intumescence in a plane perpendicular to the wall decreases exponentially with increasing distance from the side, but the crest of the wave is curved backward.


1967 ◽  
Vol 30 (3) ◽  
pp. 439-448 ◽  
Author(s):  
Walter L. Jones

In a rotating system, the vertical transport of angular momentum by internal gravity waves is independent of height, except at critical levels where the Doppler-shifted wave frequency is equal to plus or minus the Coriolis frequency. If slow rotation is ignored in studying the propagation of internal gravity waves through shear flows, the resulting solutions are in error only at levels where the Doppler-shifted and Coriolis frequencies are comparable.


2016 ◽  
Vol 56 ◽  
pp. 110-119
Author(s):  
M. Ungarish ◽  
C.G. Johnson ◽  
A.J. Hogg
Keyword(s):  

Author(s):  
K. Vijayraj ◽  
M. Govardhan

A Counter-Rotating System (CRS) is composed of a front rotor and a rear rotor which rotates in the opposite direction. Compared with traditional rotor-stator system, the rear rotor is used not only to recover the static head but also to supply energy to the fluid. Therefore, to achieve the same performance, the use of a CRS may lead to a reduction of the rotational speed and may generate better homogeneous flow downstream of the stage. On the other hand, the mixing area in between the two rotors induces complicated interacting flow structures. Blade sweep has attracted the turbomachinery blade designers owing to a variety of performance benefits it offers. However, the effect of blade sweep on the performance, stall margin improvements whether it is advantageous/disadvantageous to sweep one or both rotors has not been studied till now. In the current investigation blade sweep on the performance characteristics of contra rotating axial flow fans are studied. Two sweep schemes (axial sweeping and tip chord line sweeping) are studied for two sweep angles (20° and 30°). Effect of blade sweep on front rotor and rear rotor are dealt separately by sweeping one at a time. Both rotors are swept together and effect of such sweep scheme on the aerodynamic performance of the stage is also reported here. The performance of contra rotating fan is significantly affected by all these parameters. Blade sweep improved the pressure rise and stall margin of front rotors. Axially swept rotors are found to have higher pressure rise with reduced incidence losses near the tip for front rotors. Sweeping the rear rotor is not effective since the pressure rise is less than that of unswept rotor and also has less stall margin.


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