A Two Time Scales Turbulence Model of Turbulent Bubbly Flows

2013 ◽  
Vol 40 (3) ◽  
pp. 185-203
Author(s):  
Dhahri Maher ◽  
Bellakhel Ghazi ◽  
Chahed Jamel
Keyword(s):  
Time Scales ◽  
Turbulence Model ◽  
Bubbly Flows

Assessment of turbulence models for bubbly flows: Toward a five-equation turbulence model

2020 ◽  
Vol 220 ◽  
pp. 115425
Author(s):  
Ghazi Bellakhal ◽  
Fathia Chaibina ◽  
Jamel Chahed
Keyword(s):  
Turbulence Model ◽  
Turbulence Models ◽  
Bubbly Flows

A turbulence model for inclined, bubbly flows

1993 ◽  
Vol 51 (1-2) ◽  
pp. 263-268 ◽  
Author(s):  
S. D. Mobbs ◽  
G. P. Lucas
Keyword(s):  
Turbulence Model ◽  
Bubbly Flows

Toward a Pointwise Turbulence Model for Wall-Bounded and Free Shear Flows

1994 ◽  
Vol 116 (1) ◽  
pp. 72-76 ◽  
Author(s):  
Uriel C. Goldberg
Keyword(s):  
Time Scales ◽  
Turbulence Model ◽  
Shear Flows ◽  
Explicit Knowledge ◽  
Complex Geometries ◽  
Wall Function ◽  
Predictive Capability ◽  
Large Eddy ◽  
Local Distance ◽  
Near Wall

A modified version of the Baldwin-Barth k-ℜ two-equation turbulence model is proposed, in which the near-wall function fμ is based on the ratio of the large eddy and the Kolmogorov time scales. This results in a model applicable to both wall-bounded and free shear flows which, nevertheless, does not require explicit knowledge of local distance to walls, rendering it useful within both structured and unstructured computational frameworks for flow predictions involving complex geometries. The new model’s predictive capability is demonstrated through a number of flow cases.

A two-equation turbulence model of turbulent bubbly flows

2001 ◽  
Vol 27 (11) ◽  
pp. 1965-2000 ◽  
Author(s):  
A.A. Troshko ◽  
Y.A. Hassan
Keyword(s):  
Turbulence Model ◽  
Bubbly Flows

A dual-scale turbulence model for gas–liquid bubbly flows

2015 ◽  
Vol 23 (11) ◽  
pp. 1737-1745 ◽  
Author(s):  
Xiaoping Guan ◽  
Zhaoqi Li ◽  
Lijun Wang ◽  
Xi Li ◽  
Youwei Cheng
Keyword(s):  
Turbulence Model ◽  
Bubbly Flows ◽  
Scale Turbulence ◽  
Dual Scale

A bubble-induced turbulence model for gas-liquid bubbly flows in airlift columns, pipes and bubble columns

2020 ◽  
Vol 227 ◽  
pp. 115945 ◽  
Author(s):  
Shuli Shu ◽  
Naoufel El Bahraoui ◽  
François Bertrand ◽  
Jamal Chaouki
Keyword(s):  
Turbulence Model ◽  
Bubble Columns ◽  
Bubbly Flows

LVSEM: Past Present and Future

1990 ◽  
Vol 48 (1) ◽  
pp. 364-365
Author(s):  
James B. Pawley
Keyword(s):  
Field Emission ◽  
Line Width ◽  
Time Scales ◽  
Silicon Oxide ◽  
Beam Current ◽  
High Brightness ◽  
High Beam ◽  
Fixed Charges ◽  
Beam Voltage ◽  
Deposited Metal

Past: In 1960 Thornley published the first description of SEM studies carried out at low beam voltage (LVSEM, 1-5 kV). The aim was to reduce charging on insulators but increased contrast and difficulties with low beam current and frozen biological specimens were also noted. These disadvantages prevented widespread use of LVSEM except by a few enthusiasts such as Boyde. An exception was its use in connection with studies in which biological specimens were dissected in the SEM as this process destroyed the conducting films and produced charging unless LVSEM was used.In the 1980’s field emission (FE) SEM’s came into more common use. The high brightness and smaller energy spread characteristic of the FE-SEM’s greatly reduced the practical resolution penalty associated with LVSEM and the number of investigators taking advantage of the technique rapidly expanded; led by those studying semiconductors. In semiconductor research, the SEM is used to measure the line-width of the deposited metal conductors and of the features of the photo-resist used to form them. In addition, the SEM is used to measure the surface potentials of operating circuits with sub-micrometer resolution and on pico-second time scales. Because high beam voltages destroy semiconductors by injecting fixed charges into silicon oxide insulators, these studies must be performed using LVSEM where the beam does not penetrate so far.

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