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Investigation of shock dynamics in an axisymmetric inlet/isolator with attached boundary layers

Published online by Cambridge University Press:  15 December 2020

Michael D. Leonard  and
V. Narayanaswamy Open the ORCID record for V. Narayanaswamy [Opens in a new window]
Michael D. Leonard
Affiliation:
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
V. Narayanaswamy*
Affiliation:
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
*
†Email address for correspondence: vnaraya3@ncsu.edu
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Abstract

Shock oscillations within a model two-dimensional axisymmetric inlet with a constant area isolator are investigated under the condition of maintaining an unseparated boundary layer throughout the inlet/isolator section. Power spectral densities of the wall-pressure fluctuations beneath each shock leg intersecting the isolator surface exhibited a very low frequency broadband oscillation in the 10–100 Hz range as well as a very high frequency broadband oscillations above 10 kHz. Whereas the high frequency oscillations are attributed to the incoming boundary layer fluctuations, detailed investigations into the pressure fluctuation communication pathways within the isolator and their length scale of communication are made to elucidate the origin of the low frequency fluctuations. It was found that the downstream propagation of pressure fluctuations is primarily by the convection of the boundary layer structures and this communication occurred over several boundary layer thicknesses. The upstream propagation occurs through acoustic waves that extend over a distance of one local boundary layer thickness. Based on this understanding, a physical model is constructed, which makes an accurate prediction of pressure power spectrum of the low frequency shock wave oscillations; the model predictions also favourably compare with the shock oscillations in external shock boundary layer interactions without shock-induced flow separation.

JFM classification

Aerodynamics: High-speed flow Compressible Flows: Compressible boundary layers Compressible Flows: Shock waves

Information

Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 908 , 10 February 2021 , A42
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Copyright
© The Author(s), 2020. Published by Cambridge University Press

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References

REFERENCES

Bendat, J. & Piersol, A. 1986 Random Data, 2nd edn. John Wiley & Sons.Google Scholar
Bruce, P. J. K. & Babinsky, H. 2008 Unsteady shock wave dynamics. J. Fluid Mech. 603, 463–473.CrossRefGoogle Scholar
Carroll, B. F. & Dutton, J. C. 1990 Characteristics of multiple shock wave/turbulent boundary-layer interactions in rectangular ducts. J. Propul. Power 6 (2), 186–193.CrossRefGoogle Scholar
Crocco, L. 1958 High Speed Aerodynamics and Jet Propulstion. B, vol. 3. Princeton.Google Scholar
Curran, E. T. & Stull, F. E. 1964 The utilization of supersonic combustion ramjet systems at low Mach numbers. Tech Rep. RTD-TDR-63-4097. Aero Propulsion Lab.Google Scholar
Fiévet, R., Koo, H., Raman, V. & Auslender, A. H. 2017 Numerical investigation of shock-train response to inflow boundary-layer variations. AIAA J. 55 (11), 2888–2901.CrossRefGoogle Scholar
Funderburk, M. L. & Narayanaswamy, V. 2019 Spectral signal quality of fast pressure sensitive paint measurements in turbulent shock-wave/boundary layer interactions. Exp. Fluids 60 (10), 154.CrossRefGoogle Scholar
Geerts, J. S. & Yu, K. H. 2016 Shock train/boundary-layer interaction in rectangular isolators. AIAA J. 54 (11), 3450–3464.CrossRefGoogle Scholar
Hunt, R. L. & Gamba, M. 2018 Shock train unsteadiness characteristics, oblique-to-normal transition, and three-dimensional leading shock structure. AIAA J. 56 (4), 1569–1587.CrossRefGoogle Scholar
Hunt, R. L. & Gamba, M. 2019 On the origin and propagation of perturbations that cause shock train inherent unsteadiness. J. Fluid Mech. 861, 815–859.CrossRefGoogle Scholar
Ikui, T., Matsuo, K. & Nagai, M. 1974 a The mechanism of pseudo-shock waves. Bull. JSME 17 (108), 731–739.CrossRefGoogle Scholar
Ikui, T., Matsuo, K., Nagai, M. & Honjo, M. 1974 b Oscillation phenomena of pseudo-shock waves. Bull. JSME 17 (112), 1278–1285.CrossRefGoogle Scholar
Korkegi, R. H. 1975 Comparison of shock-induced two- and three- dimensional incipient turbulent separation. AIAA J. 26 (4), 534–535.CrossRefGoogle Scholar
Miller, J. H. 2018 Pressure scalings and influence region research. Tech Rep. AFRL Tech Briefs.Google Scholar
Pickles, J. D., Mettu, B. R., Subbareddy, P. K. & Narayanaswamy, V. 2018 Gas density field imaging in shock dominated flows using planar laser scattering. Exp. Fluids 59 (112), 1–15.CrossRefGoogle Scholar
Plotkin, K. J. 1975 Shock wave oscillation driven by turbulent boundary-layer fluctuations. AIAA J. 13 (8), 1036–1040.CrossRefGoogle Scholar
Poggie, J., Bisek, N. J., Kimmel, R. L. & Stanfield, S. A. 2015 Spectral characteristics of separation shock unsteadiness. AIAA J. 53 (1), 200–214.CrossRefGoogle Scholar
Poggie, J. & Smits, A. J. 2005 Experimental evidence for Plotkin model of shock unsteadiness in separated flow. Phys. Fluids 17 (1), 018107.CrossRefGoogle Scholar
Ramesh, M. D. & Tannehill, J. C. 2004 Correlations to predict the streamwise influence regions in supersonic turbulent flows. J. Aircraft 41 (2), 274–283.CrossRefGoogle Scholar
Smits, A. J. & Muck, K.-C. 1987 Experimental study of three shock wave/turbulent boundary layer interactions. J. Fluid Mech. 182, 291–314.CrossRefGoogle Scholar
Su, W.-Y., Ji, Y.-X. & Chen, Y. 2016 Effects of dynamic backpressure on pseudoshock oscillations in scramjet inlet-isolator. J. Propul. Power 32 (2), 516–528.CrossRefGoogle Scholar
Sugiyama, H., Takeda, H., Zhang, J., Okuda, K. & Yamagishi, H. 1988 Locations and oscillation phenomena of pseudo-shock waves in a straight rectangular duct. JSME Intl J. 31 (1), 9–15.Google Scholar
Waltrup, P. J. & Billig, F. S. 1973 Structure of shock waves in cylindrical ducts. AIAA J. 11 (10), 1404–1408.CrossRefGoogle Scholar
Xiong, B., Fan, X.-Q., Wang, Z.-G. & Tao, Y. 2018 Analysis and modelling of unsteady shock train motions. J. Fluid Mech. 846, 240–262.CrossRefGoogle Scholar
Yamane, R., Kondo, E., Tomita, Y. & Sakae, N. 1984 Vibration of pseudo-shock in straight duct : 1st report, fluctuation of static pressure. Bull. JSME 27 (229), 1385–1392.CrossRefGoogle Scholar