scholarly journals Front shock behavior of stable curved detonation waves in rectangular-cross-section curved channels

2013 ◽  
Vol 34 (2) ◽  
pp. 1939-1947 ◽  
Author(s):  
Hisahiro Nakayama ◽  
Jiro Kasahara ◽  
Akiko Matsuo ◽  
Ikkoh Funaki
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Detonation Waves ◽  
Curved Channels

A Numerical Study of Dean Instability in Non-Newtonian Fluids

2005 ◽  
Vol 128 (1) ◽  
pp. 34-41 ◽  
Author(s):  
H. Fellouah ◽  
C. Castelain ◽  
A. Ould El Moctar ◽  
H. Peerhossaini
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
Power Law ◽  
Numerical Study ◽  
Rectangular Cross Section ◽  
Newtonian Fluids ◽  
Dean Number ◽  
Bingham Number ◽  
Curved Channels ◽  
Power Law Index

We present a numerical study of Dean instability for non-Newtonian fluids in a laminar 180deg curved-channel flow of rectangular cross section. A methodology based on the Papanastasiou model (Papanastasiou, T. C., 1987, J. Rheol., 31(5), pp. 385–404) was developed to take into account the Bingham-type rheological behavior. After validation of the numerical methodology, simulations were carried out (using FLUENT CFD code) for Newtonian and non-Newtonian fluids in curved channels of square or rectangular cross section and for a large aspect and curvature ratios. A criterion based on the axial velocity gradient was defined to detect the instability threshold. This criterion was used to optimize the grid geometry. The effects of curvature and aspect ratio on the Dean instability are studied for all fluids, Newtonian and non-Newtonian. In particular, we show that the critical value of the Dean number decreases with increasing curvature ratio. The variation of the critical Dean number with aspect ratio is less regular. The results are compared to those for Newtonian fluids to emphasize the effect of the power-law index and the Bingham number. The onset of Dean instability is delayed with increasing power-law index. The same delay is observed in Bingham fluids when the Bingham number is increased.

219403 Propagation Characteristics of Detonation Waves in Rectangular Cross-Section Bends

2011 ◽  
Vol 2011.17 (0) ◽  
pp. 531-532
Author(s):  
Hisahiro NAKAYAMA ◽  
Takahiro MORIYA ◽  
Jiro KASAHARA ◽  
Akiko MATSUO ◽  
Yuya SASAMOTO
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Detonation Waves ◽  
Propagation Characteristics

scholarly journals Propagation of Curved Detonation Waves Stabilized in Annular Channels with a Rectangular Cross-section

2012 ◽  
Vol 10 (ists28) ◽  
pp. Pe_7-Pe_14
Author(s):  
Hisahiro NAKAYAMA ◽  
Takahiro MORIYA ◽  
Jiro KASAHARA ◽  
Akiko MATSUO ◽  
Yuya SASAMOTO ◽  
...  
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Detonation Waves ◽  
Annular Channels

scholarly journals Stable detonation wave propagation in rectangular-cross-section curved channels

2012 ◽  
Vol 159 (2) ◽  
pp. 859-869 ◽  
Author(s):  
Hisahiro Nakayama ◽  
Takahiro Moriya ◽  
Jiro Kasahara ◽  
Akiko Matsuo ◽  
Yuya Sasamoto ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Detonation Wave ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Curved Channels ◽  
Detonation Wave Propagation

Dean Instability in Non-Newtonian Fluids

2004 ◽  
Author(s):  
H. Fellouah ◽  
C. Castelain ◽  
A. Ould El Moctar ◽  
H. Peerhossaini
Keyword(s):  
Cross Section ◽  
Power Law ◽  
Numerical Study ◽  
Rectangular Cross Section ◽  
Newtonian Fluids ◽  
Dean Number ◽  
Bingham Number ◽  
Curved Channels ◽  
Aspect Ratios ◽  
Power Law Index

We present a numerical study of Dean instability in non-Newtonian fluids in a laminar 180° curved-channel flow of rectangular cross section. A methodology based on the Papanastasiou model [1] was developed to take into account Bingham-type rheological behavior. After validation of the numerical methodology, simulations were carried out (using Fluent CFD code) for Newtonian and non-Newtonian fluids in curved channels of square and rectangular cross section and of large aspect and curvature ratios. A criterion based on the axial velocity gradient was defined to detect the instability threshold. This criterion is used to optimize the grid geometry. The effects of curvature and aspect ratios on the instability are studied for all fluids, Newtonian and non-Newtonian. In particular, we show that the critical value of the Dean number decreases with increasing duct curvature ratio. The variation of the critical Dean number with duct aspect ratio is less regular. The results are compared with those for Newtonian fluids to emphasize the effect of the power-law index and the Bingham number. The onset of Dean instability is delayed with increasing power-law index. The same delay is observed in Bingham fluids when the Bingham number is increased.

scholarly journals Oblique detonation waves stabilized in rectangular-cross-section bent tubes

2011 ◽  
Vol 33 (2) ◽  
pp. 2319-2326 ◽  
Author(s):  
Yusuke Kudo ◽  
Yuuto Nagura ◽  
Jiro Kasahara ◽  
Yuya Sasamoto ◽  
Akiko Matsuo
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Detonation Waves
Sign in / Sign up

Export Citation Format

Share Document