Systematic studies on separation induced low-frequency unsteadiness in a canonical supersonic combustor are implemented through wind tunnel experiment and numerical simulation. With an inflow Mach number of 3, cold flow analysis has been carried out to focus on the key impact factor of flow instability. Dynamic flow features are captured by high-frequency pressure signals, and three-dimensional Reynolds-Averaged Navier-Stokes simulation is performed to represent the typical unsteady movement of the shock train. The separated flowfield shows an intrinsic instability, whose feature is the large-amplitude and low-frequency streamwise movement of the oblique shock train. The oscillation of shock train is in a broadband frequency range, and pressure signals obtained from different streamwise regions behave various features. The intermittent region and the backpressure-affected region are two major resources of oscillation energy. Numerical results represent variable-speed shock train motions with multiple amplitudes, and broadband behaviors in experiments are captured. The autocorrelation analysis shows that the broadband behavior of the unsteadiness is not caused by the white noise. From the coherence analysis, it is found that two kinds of oscillation modes (independent and synchronous) exist in the flowfield. The independent mode exists extensively in the unstable flow, while the synchronous mode only appears occasionally and is always suppressed in the very-low-frequency band (below 80 Hz). Repeated experiments indicate that signals from these two oscillation modes superpose randomly. The phase analysis reveals that the backpressure is the original source of this complicated unstable separated flow.
REFERENCES
1.
M. A.
Frost
, D. Y.
Gangurde
, A.
Paull
, and D. J.
Mee
, “Boundary-layer separation due to combustion-induced pressure rise in a supersonic flow
,” AIAA J.
47
, 1050
(2009
).2.
M. B.
Sun
, Z.
Zhong
, J. H.
Liang
, and Z. G.
Wang
, “Experimental investigation of supersonic model combustor with distributed injection of supercritical kerosene
,” J. Propul. Power
30
, 1537
(2015
).3.
T. O.
Mohieldin
, S. N.
Tiwari
, and M. J.
Olynciw
, “Asymmetric flow-structures in dual mode scramjet combustor with significant upstream interaction
,” AIAA Paper 2001-3296, 2001
.4.
C.
Rodriquez
, “Asymmetry effects in numerical simulation of supersonic flows with upstream separated regions
,” AIAA Paper 2001-0084, 2001
.5.
M.
Sun
, Z.
Zhong
, T.
Gao
, H.
Wang
, and J.
Liang
, “Asymmetric combustion characteristics of transverse ethylene injection in a rectangular supersonic combustor with single-side expansion
,” AIAA Paper 2017-2233, 2017
.6.
T.
Gao
, J.
Liang
, M.
Sun
, and Z.
Zhong
, “Dynamic combustion characteristics in a rectangular supersonic combustor with single-side expansion
,” Proc. Inst. Mech. Eng., Part G
231
, 1862
(2017
).7.
D. S.
Dolling
and C. T.
Or
, “Unsteadiness of the shock wave structure in attached and separated compression ramp flows
,” Exp. Fluids
3
, 24
(1985
).8.
D.
Dolling
and S.
Bogdonoff
, “An experimental investigation of the unsteady behavior of blunt fin-induced shock wave turbulent boundary layer interaction
,” AIAA Paper 1981-1287, 1981
.9.
R. A.
Humble
, G. E.
Elsinga
, F.
Scarano
, and B. W. V.
Oudheusden
, “Three-dimensional instantaneous structure of a shock wave/turbulent boundary layer interaction
,” J. Fluid Mech.
622
, 33
(2009
).10.
S.
Priebe
and M. P.
Martín
, “Low-frequency unsteadiness in shock wave-turbulent boundary layer interaction
,” J. Fluid Mech.
699
, 1
(2012
).11.
V.
Pasquariello
, S.
Hickel
, and N. A.
Adams
, “Unsteady effects of strong shock-wave/boundary-layer interaction at high Reynolds number
,” J. Fluid Mech.
823
, 617
(2017
).12.
S.
Piponniau
, J. P.
Dussauge
, J. F.
Debiève
, and P.
Dupont
, “A simple model for low-frequency unsteadiness in shock-induced separation
,” J. Fluid Mech.
629
, 87
(2009
).13.
N. T.
Clemens
and V.
Narayanaswamy
, “Low-frequency unsteadiness of shock wave/turbulent boundary layer interactions
,” Annu. Rev. Fluid. Mech.
46
, 469
(2014
).14.
H.
Do
, S. K.
Im
, M. G.
Mungal
, and M. A.
Cappelli
, “The influence of boundary layers on supersonic inlet flow unstart induced by mass injection
,” Exp. Fluids
51
, 679
(2011
).15.
Q. F.
Zhang
, H. J.
Tan
, S.
Sun
, H. X.
Bu
, and C. Y.
Rao
, “Unstart of a hypersonic inlet with side compression caused by downstream choking
,” AIAA J.
54
, 28
(2016
).16.
N.
Li
, J.-T.
Chang
, K.-J.
Xu
, D.-R.
Yu
, W.
Bao
, and Y.-P.
Song
, “Oscillation of the shock train in an isolator with incident shocks
,” Phys. Fluids
30
, 116102
(2018
).17.
B.
Xiong
, X. Q.
Fan
, Y.
Wang
, L.
Zhou
, and Y.
Tao
, “Back-pressure effects on unsteadiness of separation shock in a rectangular duct at Mach 3
,” Acta Astronaut.
141
, 248
(2017
).18.
B.
Xiong
, Z. G.
Wang
, X. Q.
Fan
, and Y.
Wang
, “Response of shock train to high-frequency fluctuating backpressure in an isolator
,” J. Propul. Power
33
, 1520
(2017
).19.
B.
Xiong
, X.-Q.
Fan
, Z.-G.
Wang
, and Y.
Tao
, “Analysis and modelling of unsteady shock train motions
,” J. Fluid Mech.
846
, 240
(2018
).20.
D.
Papamoschou
and A.
Zill
, “Fundamental investigation of supersonic nozzle flow separation
,” AIAA Paper 2004-1111, 2004
.21.
D.
Papamoschou
and A. D.
Johnson
, “Unsteady phenomena in supersonic nozzle flow separation
,” AIAA Paper 2006-3360, 2006
.22.
D.
Papamoschou
, A.
Zill
, and A.
Johnson
, “Supersonic flow separation in planar nozzles
,” Shock Waves
19
, 171
(2009
).23.
A. D.
Johnson
and D.
Papamoschou
, “Instability of shock-induced nozzle flow separation
,” Phys. Fluids
22
, 016102
(2010
).24.
B. J.
Olson
and S. K.
Lele
, “A mechanism for unsteady separation in over-expanded nozzle flow
,” Phys. Fluids
25
, 110809
(2013
).25.
B. J.
Olson
and S. K.
Lele
, “Directional artificial fluid properties for compressible large-eddy simulation
,” J. Comput. Phys.
246
, 207
(2013
).26.
Y.
Yu
, J.
Xu
, K.
Yu
, and J.
Mo
, “Unsteady transitions of separation patterns in single expansion ramp nozzle
,” Shock Waves
25
, 623
(2015
).27.
T.
Gao
, J.
Liang
, and M.
Sun
, “Decoupling analysis on oscillation of separated region in a supersonic combustor with single-side expansion
,” J. Propul. Technol.
39
, 2381
(2018
) (in Chinese).28.
T.
Gao
, J.
Liang
, M.
Sun
, and Y.
Zhao
, “Analysis of separation modes variation in a scramjet combustor with single-side expansion
,” AIAA J.
55
, 1307
(2017
).29.
T.
Gao
, J.
Liang
, and M.
Sun
, “Symmetric/asymmetric separation transition in a supersonic combustor with single-side expansion
,” Phys. Fluids
29
, 126102
(2017
).30.
Y. H.
Zhao
, J. H.
Liang
, Y. X.
Zhao
, and Y. J.
Zhang
, “Research on passive control of jet in supersonic crossflow based on micro-vortex generator
,” J. Propul. Technol.
37
, 801
(2016
) (in Chinese).31.
Y. H.
Zhao
, “Research on gaseous fuel mixing mechanism of transverse jet in scramjet engine
,” Ph.D. thesis, National University of Defense Technology
, 2016
.32.
Y.
Zhao
, S.
Yi
, L.
Tian
, and Z.
Cheng
, “Supersonic flow imaging via nanoparticles
,” Sci. China, Ser. E: Technol. Sci.
52
, 3640
(2009
).33.
W.
Zhenguo
, Z.
Yilong
, Z.
Yuxin
, and F.
Xiaoqiang
, “Prediction of massive separation of unstarted inlet via free-interaction theory
,” AIAA J.
53
, 1108
(2015
).34.
P.
Quan
, S.
Yi
, W.
Yu
, Y.
Zhu
, and H.
Lin
, “Experimental investigation on the effects of swept angles on blunt fin-induced flow
,” AIAA J.
53
, 2805
(2015
).35.
Q.-C.
Wang
, Z.-G.
Wang
, and Y.-X.
Zhao
, “On the impact of adverse pressure gradient on the supersonic turbulent boundary layer
,” Phys. Fluids
28
, 116101
(2016
).36.
Q.-C.
Wang
, Z.-G.
Wang
, and Y.-X.
Zhao
, “An experimental investigation of the supersonic turbulent boundary layer subjected to concave curvature
,” Phys. Fluids
28
, 096104
(2016
).37.
Q. C.
Wang
, Z. G.
Wang
, and Y. X.
Zhao
, “The impact of streamwise convex curvature on the supersonic turbulent boundary layer
,” Phys. Fluids
29
, 116106
(2017
).38.
S.
Ming-bo
, L.
Jing
, W.
Hai-yan
, L.
Jian-han
, L.
Wei-dong
, and W.
Zhen-guo
, “Flow patterns and mixing characteristics of gaseous fuel multiple injections in a non-reacting supersonic combustor
,” Heat Mass Transfer
47
, 1499
(2011
).39.
B.
Wang
, N. D.
Sandham
, Z.
Hu
, and W.
Liu
, “Numerical study of oblique shock-wave/boundary-layer interaction considering sidewall effects
,” J. Fluid Mech.
767
, 526
(2015
).40.
D. B.
Le
, C. P.
Goyne
, and R. H.
Krauss
, “Shock train leading-edge detection in a dual-mode scramjet
,” J. Propul. Power
24
, 1035
(2008
).41.
B.
Xiong
, Z.
Wang
, X.
Fan
, and Y.
Wang
, “A method for shock train leading edge detection based on differential pressure
,” Proc. Inst. Mech. Eng., Part G
231
, 61
(2016
).42.
O.
Olabiyi
and A.
Annamalai
, “Analysis and new implementations of periodogram-based spectrum sensing
,” in 35th IEEE Sarnoff Symposium
(IEEE
, 2012
).43.
E.
Martelli
, P. P.
Ciottoli
, L.
Saccoccio
, F.
Nasuti
, M.
Valorani
, and M.
Bernardini
, “Characterization of unsteadiness in an overexpanded planar nozzle
,” AIAA J.
57
, 239
(2018
).44.
J. T.
Gosling
and S. J.
Bame
, “Solar-wind speed variations 1964–1967: Autocorrelation analysis
,” J. Geophys. Res.
77
, 12
, https://doi.org/10.1029/ja077i001p00012 (1972
).45.
L. R.
Rabiner
, “On the use of autocorrelation analysis for pitch detection
,” IEEE Trans. Acoust., Speech, Signal Process.
25
, 24
(1977
).46.
S.
Hussain
and A.
Al-Alili
, “A new approach for model validation in solar radiation using wavelet, phase and frequency coherence analysis
,” Appl. Energy
164
, 639
(2016
).47.
J.
Gosselin
, “Comparative study of two-sensor(magnitude-squared coherence) and single-sensor(square-law) receiver operating characteristics
,” IEEE International Conference on Acoustics, Speech, and Signal Processing, 9–11 May 1977
, p. 311
.48.
M.
Sun
, Z.
Hu
, and N. D.
Sandham
, “Recovery of a supersonic turbulent boundary layer after an expansion corner
,” Phys. Fluids
29
, 076103
(2017
).49.
L.
Brusniak
and D. S.
Dolling
, “Physics of unsteady blunt-fin-induced shock wave/turbulent boundary layer interactions
,” J. Fluid Mech.
273
, 375
(1994
).50.
P.
Dupont
, C.
Haddad
, and J. F.
Debieve
, “Space and time organization in a shock-induced separated boundary layer
,” J. Fluid Mech.
559
, 255
(2006
).51.
D. S.
Dolling
and M. E.
Erengil
, “Unsteady wave structure near separation in a Mach 5 compression rampinteraction
,” AIAA J.
29
, 728
(1991
).© 2019 Author(s).
2019
Author(s)
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