Force- and Loss-Free Transitions Between Vortex Flow States

1987 ◽  
pp. 63-75 ◽  
Author(s):  
J. J. Keller ◽  
W. Egli ◽  
J. Exley
Keyword(s):  
Vortex Flow ◽  
Flow States

scholarly journals Coherent and incoherent vortex flow states in crossed channels

2009 ◽  
Vol 88 (4) ◽  
pp. 47004 ◽  
Author(s):  
C. J. Olson Reichhardt ◽  
C. Reichhardt
Keyword(s):  
Vortex Flow ◽  
Flow States

Spatial and temporal characteristics of modulated waves in the circular Couette system

1982 ◽  
Vol 117 ◽  
pp. 123-142 ◽  
Author(s):  
M. Gorman ◽  
Harry L. Swinney
Keyword(s):  
Flow Visualization ◽  
Phase Angle ◽  
Vortex Flow ◽  
Space Time ◽  
Single Frequency ◽  
Taylor Vortex ◽  
Periodic Flow ◽  
Periodic Regime ◽  
Azimuthal Waves ◽  
Flow States

We have used flow-visualization and spectral techniques to study the spatial and temporal properties of the flow that precedes the onset of weak turbulence in a fluid contained between concentric cylinders with the inner cylinder rotating (the circular Couette system). The first three flow regimes encountered as the Reynolds number is increased from zero are well-known – Couette flow, Taylor-vortex flow, and wavyvortex flow. The present study concerns the doubly periodic regime that follows the (singly periodic) wavy-vortex-flow regime. Wavy-vortex flow is characterized by a single frequency f1, which is the frequency of travelling azimuthal waves passing a point of observation in the laboratory. The doubly periodic regime was discovered in studies of power spectra several years ago, but the fluid motion corresponding to the second frequency f2 was not identified. We have found that f2 corresponds to a modulation of the azimuthal waves; the modulation can be observed visually as a periodic flattening of the wavy-vortex outflow boundaries. Moreover, in addition to the previously observed doubly periodic flow state, we have discovered 11 more doubly periodic flow states. Each state can be labelled with two integers m and k, which are simply related to physical characteristics of the flow: m is the number of azimuthal waves, and k is related to the phase angle between the modulation of successive azimuthal waves by Δϕ = 2πk/m. This expression for the phase angle was first conjectured from the flow-visualization measurements and then tested to an accuracy of 0·01π in spectral measurements. Recently Rand (1981) has used dynamical-systems concepts and symmetry considerations to derive predictions about the space–time symmetry of doubly periodic flows in circularly symmetric systems. He predicted that only flows with certain space–time symmetries should be allowed. The observed flow states are in agreement with this theory.

ANALISIS VARIASI JUMLAH SUDU TURBIN BERPENAMPANG PELAT DATAR PADA TURBIN AIR ALIRAN VORTEX DENGAN TIPE SALURAN MASUK INVOLUTE

2020 ◽  
Vol 7 (2) ◽  
pp. 72-78
Author(s):  
Adnan Al Farisi ◽  
Yopi Handoyo ◽  
Taufiqur Rokhman
Keyword(s):  
Power Plant ◽  
Alternative Energy ◽  
Vortex Flow ◽  
Experimental Methods ◽  
Turbine Efficiency ◽  
A Value ◽  
Current Voltage ◽  
Materials Research ◽  
The One ◽  
Flow Vortex

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know  the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.

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