The vortex-in-cell method for the study of three-dimensional vortex structures

2005 ◽  
pp. 49-54 ◽  
Author(s):  
Henryk Kudela ◽  
Pawel Regucki
Keyword(s):  
Three Dimensional ◽  
Vortex Structures ◽  
Cell Method

GHOST-CELL METHOD FOR INVISCID THREE-DIMENSIONAL FLOWS WITH MOVING BODY ON CARTESIAN GRIDS

2009 ◽  
Vol 23 (03) ◽  
pp. 277-280
Author(s):  
JIANMING LIU ◽  
NING ZHAO ◽  
OU HU
Keyword(s):  
Three Dimensional ◽  
Small Cell ◽  
Special Treatment ◽  
Ghost Cell ◽  
Cartesian Grids ◽  
Cell Problem ◽  
Cell Method ◽  
Moving Body ◽  
Ghost Cell Method ◽  
Moving Bodies

This paper depicts a ghost cell method to solve the three dimensional compressible time-dependent Euler equations using Cartesian grids for static or moving bodies. In this method, there is no need for special treatment corresponding to cut cells, which complicate other Cartesian mesh methods, and the method avoids the small cell problem. As an application, we present some numerical results for a special moving body using this method, which demonstrates the efficiency of the proposed method.

Three-dimensional vortex structures in cavities

1981 ◽  
Vol 22 (2) ◽  
pp. 186-189 ◽  
Author(s):  
V. D. Zhak ◽  
V. A. Mukhin ◽  
V. E. Nakoryakov
Keyword(s):  
Three Dimensional ◽  
Vortex Structures

Three-Dimensional Gyrotron Simulation Using a High-Order Particle-in-Cell Method

2012 ◽  
pp. 637-649 ◽  
Author(s):  
A. Stock ◽  
J. Neudorfer ◽  
B. Steinbusch ◽  
T. Stindl ◽  
R. Schneider ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Order ◽  
Particle In Cell ◽  
Cell Method

Mechanism of Fast Transition of Pressure Pulsations in the Vaneless Space of a Model Pump-Turbine During Runaway

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Xiaoxi Zhang ◽  
Wei Zeng ◽  
Yongguang Cheng ◽  
Zhiyan Yang ◽  
Qiuhua Chen ◽  
...  
Keyword(s):  
Transient Flow ◽  
Characteristic Curve ◽  
Three Dimensional ◽  
Low Frequency ◽  
Vortex Structures ◽  
Pressure Pulsations ◽  
Pump Turbine ◽  
Whole Process ◽  
Time Variations ◽  
Flow Vortex

The pressure pulsations in the vaneless space of pump-turbines are extremely intense and always experience rapid time variations during transient scenarios, causing structural vibrations and even more serious accidents. In this study, the mechanism behind the rapid time variations of the vaneless space pressure pulsations in a model pump-turbine during runaway was analyzed through three-dimensional (3D) numerical simulations. These results show that the high-frequency pressure pulsation components originating from rotor–stator interactions (RSI) are dominant during the whole process. These components fluctuate significantly in frequency when the working point goes through the S-shaped region of the characteristic curve, with the amplitudes increasing. Meanwhile, some low-frequency pulsations are also enhanced and become obvious. These features can be attributed to the transitions of the inter blade vortex structures (IBVSs) to the forward flow vortex structures (FFVSs) and the back flow vortex structures (BFVSs) at the impeller entrance, when the pump-turbine operates in the region with S-shaped characteristics. The FFVSs mainly cause decreases in frequency and introduce low-frequency pulsations, while the BFVSs are responsible for the unstable fluctuations. These findings contribute to the understanding of how transient flow patterns evolve and may provide new ideas about avoiding severe pressure pulsations caused by rotating stalls in the pump-turbine during transient scenarios.

620 Developmemt of small inlet disturbances into three-dimensional vortex structures in the flow behind a backward-facing step

2001 ◽  
Vol 2001.39 (0) ◽  
pp. 241-242
Author(s):  
Masaharu YAMASAKI ◽  
Genta KAWAHARA ◽  
Shinichiro YANASE ◽  
Junji OCHI
Keyword(s):  
Three Dimensional ◽  
Vortex Structures ◽  
Backward Facing Step

S0502-1-5 Three-Dimensional Vortex Structures in a Pulsed Rectangular Jet

2010 ◽  
Vol 2010.2 (0) ◽  
pp. 151-152
Author(s):  
Kazuhei SUGIBUCHI ◽  
Shouichiro IIO ◽  
Yoshiaki HANEDA ◽  
Toshihiko IKEDA
Keyword(s):  
Three Dimensional ◽  
Vortex Structures ◽  
Rectangular Jet

Coherent Streamwise Vortex Structures in the Near-Field of the Three-Dimensional Wall Jet

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Lhendup Namgyal ◽  
Joseph W. Hall
Keyword(s):  
Velocity Field ◽  
Near Field ◽  
Three Dimensional ◽  
Vortex Pair ◽  
Streamwise Vortex ◽  
Vortex Structures ◽  
Stereoscopic Particle Image Velocimetry ◽  
Wall Jet ◽  
Streamwise Vorticity ◽  
Low Dimensional

A turbulent three-dimensional wall jet with an exit Reynolds number of 250,000 was investigated using stereoscopic particle image velocimetry (PIV) in the near-field region (x/D = 5). The proper orthogonal decomposition (POD) was applied to all three components of the velocity field to investigate the underlying coherent structures in the flow. A low-dimensional reconstruction of the turbulent velocity field using the first five POD modes showed the presence of coherent streamwise vortex structures formed in the outer shear-layers of the wall jet, not unlike those found in the near-field of free jets. The instantaneous streamwise vorticity reconstructed from the low-dimensional reconstructed velocity field indicates the presence of a persistent vortex pair close to the wall and on either side of the jet centerline that appear similar to the mean streamwise vorticity. These regions do not appear to be directly related to the positioning of the streamwise vortex structures in the outer shear-layer.

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