scholarly journals Unsteady Flow of a Nanofluid over a Sphere with Nonlinear Boussinesq Approximation

2019 ◽  
Vol 33 (2) ◽  
pp. 343-355 ◽  
Author(s):  
B. Vasu ◽  
Rama Subba Reddy Gorla ◽  
O. Anwar Bég ◽  
P. V. S. N. Murthy ◽  
V. R. Prasad ◽  
...  
Keyword(s):  
Unsteady Flow ◽  
Boussinesq Approximation

Effect of Wave Instabilities in Thermal and Solutal Mixing of Double-Diffusive Opposed Jets Impinging in a Passive-Mixer

2021 ◽  
Author(s):  
Saleem Anwar Khan ◽  
Nadeem Hasan
Keyword(s):  
Unsteady Flow ◽  
Flow Regime ◽  
Landau Theory ◽  
Travelling Waves ◽  
Unsteady Flows ◽  
Boussinesq Approximation ◽  
Bulk Velocity ◽  
Flow Mode ◽  
Passive Mixer ◽  
Neutral Curves

Abstract 2-D numerical experiments are performed to investigate the flow instabilities and mixing of different non-isothermal counterflowing jets in a Passive-Mixer. The fluid is modelled as a binary mixture with thermal and solutal buoyancy effects considered through the Boussinesq approximation. The streams are arranged in a thermal and solutal buoyancy aiding configuration. Computations are carried out for three different ratios of the upper jet bulk velocity to the lower jet bulk velocity (VR), namely, VR = 0.5, 1.0 and 2. Within the parametric domain of RiT and RiC defined by region (RiT + RiC) = 3, the instability causing transition from steady to unsteady flow regime is observed for VR = 1 and 2 while no transition is found to occur at VR = 0.5. Using Landau theory, it is established that the transition from steady to unsteady flow regime is a supercritical Hopf bifurcation. A complete regime map identifying the steady and unsteady flow regimes, within the parametric space of the present study, is obtained by plotting the neutral curves of RiC and RiT (obtained using Landau theory) for different values of VR. POD analysis of the unsteady flows at VR = 1, establishes the presence of standing waves. However, for VR = 2, the presence of degenerate pairs in the POD eigenspectrum ascertains the presence of travelling waves in the unsteady flows. The standing wave unsteady flow mode is found to yield the highest rate of mixing.

Unsteady flow calculations with a parallel multiblock moving mesh algorithm

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 1021-1029 ◽  
Author(s):  
H. M. Tsai ◽  
A. S. F. Wong ◽  
J. Cai ◽  
Y. Zhu ◽  
F. Liu
Keyword(s):  
Unsteady Flow ◽  
Moving Mesh

Dynamic effects on high frequency unsteady flow structures

1990 ◽  
Author(s):  
JOHN KLINGE ◽  
SCOTT SCHRECK ◽  
MARVIN LUTTGES
Keyword(s):  
Unsteady Flow ◽  
High Frequency ◽  
Flow Structures ◽  
Dynamic Effects

Pressure sensitive paint for unsteady flow fields

2001 ◽  
Author(s):  
Hirotaka Sakaue ◽  
James Gregory ◽  
John Sullivan ◽  
Surya Raghu
Keyword(s):  
Unsteady Flow ◽  
Flow Fields ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive
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