Application of a High-Resolution Compact Finite Difference Method to Computational Aeroacoustics of Compressible Flows

2011 ◽  
Author(s):  
Zhifeng Zuo ◽  
Hiroshi Maekawa
Keyword(s):  
Shock Wave ◽  
High Resolution ◽  
Flow Field ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Compressible Flows ◽  
Compact Finite Difference Method ◽  
Reflected Shock ◽  
Planar Shock ◽  
Planar Shock Wave

WCNS is an efficient high-resolution nonlinear scheme for solving flow-fields including discontinuity. In the present paper, a two-dimensional, unsteady, compressible flow field produced by the interaction between a strong planar shock wave and a strong vortex are simulated numerically using WCNS. The simulation shows the effects of the vortex on a planar shock and the production of acoustic waves by the shock-vortex interaction. At the early times of interaction, the shock wave is perturbed by the vortex and a precursor is produced; with the shock wave emerges from the vortex flow field, a Mach structure was generated and the secondary acoustic wave was formed by the interaction of the reflected shock (MR2) with the precursor. Both components of acoustic wave (the precursor and the second sound wave) propagate radially and have a quadrupolar nature. By this simulation, the ability of WCNS for computational aeroacoustic problems is confirmed.

scholarly journals Interaction of two-dimensional spots with a heat releasing/absorbing shock wave: linear interaction approximation results

2019 ◽  
Vol 871 ◽  
pp. 865-895 ◽  
Author(s):  
G. Farag ◽  
P. Boivin ◽  
P. Sagaut
Keyword(s):  
Shock Wave ◽  
Compressible Flows ◽  
Two Dimensional ◽  
Extended Version ◽  
Unified Framework ◽  
Linear Interaction ◽  
Planar Shock ◽  
Planar Shock Wave ◽  
Gaussian Disturbance ◽  
Interaction Approximation

The canonical interaction between a two-dimensional weak Gaussian disturbance (entropy spot, density spot, weak vortex) with an exothermic/endothermic planar shock wave is studied via the linear interaction approximation. To this end, a unified framework based on an extended Kovásznay decomposition that simultaneously accounts for non-acoustic density disturbances along with a poloidal–toroidal splitting of the vorticity mode and for heat release is proposed. An extended version of Chu’s definition for the energy of disturbances in compressible flows encompassing multi-component mixtures of gases is also proposed. This new definition precludes spurious non-normal phenomena when computing the total energy of extended Kovásznay modes. Detailed results are provided for three cases, along with fully general expressions for mixed solutions that combine incoming vortical, entropy and density disturbances.

scholarly journals Analysis of transonic buffet using dynamic mode decomposition

2021 ◽  
Vol 62 (4) ◽  
Author(s):  
Antje Feldhusen-Hoffmann ◽  
Christian Lagemann ◽  
Simon Loosen ◽  
Pascal Meysonnat ◽  
Michael Klaas ◽  
...  
Keyword(s):  
Shock Wave ◽  
Flow Field ◽  
Acoustic Waves ◽  
Feedback Loop ◽  
Measurement Data ◽  
Dynamic Mode Decomposition ◽  
Recirculation Region ◽  
Dynamic Mode ◽  
Mode Decomposition ◽  
Transonic Buffet

AbstractThe buffet flow field around supercritical airfoils is dominated by self-sustained shock wave oscillations on the suction side of the wing. Theories assume that this unsteadiness is driven by a feedback loop of disturbances in the flow field downstream of the shock wave whose upstream propagating part is generated by acoustic waves. High-speed particle-image velocimetry measurements are performed to investigate this feedback loop in transonic buffet flow over a supercritical DRA 2303 airfoil. The freestream Mach number is $$M_{\infty } = 0.73$$ M ∞ = 0.73 , the angle of attack is $$\alpha = 3.5^{\circ }$$ α = 3 . 5 ∘ , and the chord-based Reynolds number is $${\mathrm{Re}}_{c} = 1.9\times 10^6$$ Re c = 1.9 × 10 6 . The obtained velocity fields are processed by sparsity-promoting dynamic mode decomposition to identify the dominant dynamic features contributing strongest to the buffet flow field. Two pronounced dynamic modes are found which confirm the presence of two main features of the proposed feedback loop. One mode is related to the shock wave oscillation frequency and its shape includes the movement of the shock wave and the coupled pulsation of the recirculation region downstream of the shock wave. The other pronounced mode represents the disturbances which form the downstream propagating part of the proposed feedback loop. The frequency of this mode corresponds to the frequency of the acoustic waves which are generated by these downstream traveling disturbances and which form the upstream propagating part of the proposed feedback loop. In this study, the post-processing, i.e., the DMD, is highlighted to substantiate the existence of this vortex mode. It is this vortex mode that via the Lamb vector excites the shock oscillations. The measurement data based DMD results confirm numerical findings, i.e., the dominant buffet and vortex modes are in good agreement with the feedback loop suggested by Lee. Graphic abstract

scholarly journals Planar shock wave sliding over a water layer

2016 ◽  
Vol 57 (8) ◽  
Author(s):  
V. Rodriguez ◽  
G. Jourdan ◽  
A. Marty ◽  
A. Allou ◽  
J.-D. Parisse
Keyword(s):  
Shock Wave ◽  
Water Layer ◽  
Planar Shock ◽  
Planar Shock Wave

Flow of a planar shock wave around a thermal layer at a rigid wall

1991 ◽  
Vol 31 (3) ◽  
pp. 354-361
Author(s):  
B. I. Zaslavskii ◽  
S. Yu. Morozkin ◽  
A. A. Prokof'ev ◽  
V. R. Shlegel'
Keyword(s):  
Shock Wave ◽  
Rigid Wall ◽  
Planar Shock ◽  
Planar Shock Wave ◽  
Thermal Layer
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