Numerical study of transonic shock buffet instability mechanism

2016 ◽  
Author(s):  
Yi Liu ◽  
Gang Wang ◽  
Shi-bin Zhu ◽  
Zhengyin Ye
Keyword(s):  
Numerical Study ◽  
Instability Mechanism ◽  
Transonic Shock

Thermocapillary flow regimes and instability caused by a gas stream along the interface

2013 ◽  
Vol 714 ◽  
pp. 644-670 ◽  
Author(s):  
V. Shevtsova ◽  
Y. A. Gaponenko ◽  
A. Nepomnyashchy
Keyword(s):  
Marangoni Number ◽  
Gas Flow ◽  
Marangoni Convection ◽  
Silicone Oil ◽  
Numerical Study ◽  
Axial Direction ◽  
Horizontal Layer ◽  
Thermocapillary Flow ◽  
Instability Mechanism ◽  
Cold Side

AbstractWe present the results of a numerical study of the thermocapillary (Marangoni) convection in a liquid bridge of $\mathit{Pr}= 12$ ($n$-decane) and $\mathit{Pr}= 68$ (5 cSt silicone oil) when the interface is subjected to an axial gas stream. The gas flow is co- or counter-directed with respect to the Marangoni flow. In the case when the gas stream comes from the cold side, it cools down the interface to a temperature lower than that of the liquid beneath and in a certain region of the parameter space that cooling causes an instability due to a temperature difference in the direction perpendicular to the interface. The disturbances are swept by the thermocapillary flow to the cold side, which leads to the appearance of axisymmetric waves propagating in the axial direction from the hot to cold side. The mechanism of this new two-dimensional oscillatory instability is similar to that of the Pearson’s instability of the rest state in a thin layer heated from below (Pearson, J. Fluid Mech., vol. 4, 1958, p. 489), and it appears at the value of the transverse Marangoni number ${ \mathit{Ma}}_{\perp }^{cr} \approx 39\text{{\ndash}} 44$ lower than that of the Pearson’s instability in a horizontal layer ($48\lt { \mathit{Ma}}_{\perp }^{cr} \lt 80$, depending on the Biot number). The generality of the instability mechanism indicates that it is not limited to cylindrical geometry and might be observed in a liquid layer with cold gas stream.

Experimental and Numerical Study of Oscillating Transonic Shock Waves in Ducts

AIAA Journal ◽  
2011 ◽  
Vol 49 (8) ◽  
pp. 1710-1720 ◽  
Author(s):  
P. J. K. Bruce ◽  
H. Babinsky ◽  
B. Tartinville ◽  
C. Hirsch
Keyword(s):  
Shock Waves ◽  
Numerical Study ◽  
Transonic Shock

Numerical Study of Effect of the Number of Propeller Blades on Cavitating Flow

2013 ◽  
Vol 716 ◽  
pp. 739-743
Author(s):  
Zhi Feng Zhu
Keyword(s):  
Axial Velocity ◽  
Bubble Dynamics ◽  
Volume Fraction ◽  
Numerical Study ◽  
Navier Stokes ◽  
Instability Mechanism ◽  
Sliding Mesh ◽  
Propeller Wake ◽  
Hybrid Grid ◽  
Propeller Blades

The instability mechanism of propeller wake was investigated numerically on three propellers with different the numbers of blades. With the hybrid grid strategy and the sliding mesh, the Unsteady Navier-Stokes (N-S) and the Bubble Dynamics equations were solved to predict the axial velocity around the propellers and the vapor volume fraction in the blades surface. With the increasing of the numbers of propeller blades, the distance of the interaction decreases, and then the instability phenomena of the propellers wake are hastened.

Rayleigh–Marangoni oscillatory instability in a horizontal liquid layer heated from above: coupling and mode mixing of internal and surface dilational waves

2000 ◽  
Vol 405 ◽  
pp. 57-77 ◽  
Author(s):  
A. YE. REDNIKOV ◽  
P. COLINET ◽  
M. G. VELARDE ◽  
J. C. LEGROS
Keyword(s):  
Surface Tension ◽  
Surface Waves ◽  
Liquid Layer ◽  
Experimental Test ◽  
Numerical Study ◽  
Resonant Interaction ◽  
Oscillatory Instability ◽  
Open Surface ◽  
Instability Mechanism ◽  
Mode Mixing

An oscillatory instability mechanism is identified for a horizontal liquid layer with undeformable open surface heated from the air side. Although buoyancy and surface tension gradients are expected to play a stabilizing role in this situation, we show that, acting together, they may lead to the instability of the motionless state of the system. The instability is a consequence of the coupling between internal and surface waves, whose resonant interaction and resulting mode mixing are discussed. Predictions amenable to experimental test are given together with a thorough analytical and numerical study of the problem.

Numerical Study of Transonic Shock Buffet Control over a Supercritical Airfoil

2020 ◽  
Vol 57 (6) ◽  
pp. 1242-1251
Author(s):  
Yuichi Kuya ◽  
Kenshiro Boda ◽  
Keisuke Sawada
Keyword(s):  
Numerical Study ◽  
Supercritical Airfoil ◽  
Transonic Shock
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