RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods

Santanu Ghosh, Jung Il Choi, Jack R. Edwards

Research output: Chapter in Book/Report/Conference proceedingConference contribution

18 Citations (Scopus)

Abstract

This work presents an immersed boundary (IB) technique for compressible, turbulent flows and applies the technique to simulate the effects of micro vortex generators (micro VGs) in controlling oblique-shock / turbulent boundary layer interactions. Both Reynolds averaged Navier-Stokes (RANS) and hybrid large-eddy / Reynolds-averaged Navier-Stokes (LES/RANS) turbulence closures are used with the IB technique. The approach is validated by comparing RANS and hybrid LES/RANS solutions obtained using the IB technique with RANS solutions obtained using a body-fitted mesh and with experimental laser Doppler anemometry (LDA) data collected at Cambridge University for Mach 2.5 flow over a single micro VG. Simulations of an impinging oblique shock / boundary layer interaction at Mach 2.5 with and without micro VG flow control are also performed, considering a.) the development of the entire flow in the wind tunnel using a RANS model and b.) an idealized, nominally two-dimensional interaction using both the RANS and the LES/RANS models Comparisons are made with experimental LDA data and surface pressure measurements from Cambridge University, and an analysis of the flow structure is performed. The results show that three-dimensional effects initiated by the interaction of the oblique shock with the sidewall boundary layers significantly influence the flow patterns in the actual experiment. The general features of the interactions with and without the micro VG array are predicted to good accord by the RANS / IB model. Results for the idealized interaction show the LES/RANS model captures a faster recovery of the separated boundary layer and a broader influence of the vortices generated by the micro VG array, compared with the RANS model.

Original languageEnglish
Title of host publication38th AIAA Fluid Dynamics Conference and Exhibit
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781563479427
DOIs
Publication statusPublished - 2008 Jan 1

Fingerprint

Vortex flow
Boundary layers
Mach number
Lasers
Surface measurement
Flow structure
Pressure measurement
Flow control
Flow patterns
Turbulent flow
Wind tunnels
Turbulence
Recovery
Experiments

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Ghosh, S., Choi, J. I., & Edwards, J. R. (2008). RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods. In 38th AIAA Fluid Dynamics Conference and Exhibit [2008-3728] American Institute of Aeronautics and Astronautics Inc.. https://doi.org/10.2514/6.2008-3728
Ghosh, Santanu ; Choi, Jung Il ; Edwards, Jack R. / RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods. 38th AIAA Fluid Dynamics Conference and Exhibit. American Institute of Aeronautics and Astronautics Inc., 2008.
@inproceedings{67f2485d5128420eaed4497ac2661543,
title = "RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods",
abstract = "This work presents an immersed boundary (IB) technique for compressible, turbulent flows and applies the technique to simulate the effects of micro vortex generators (micro VGs) in controlling oblique-shock / turbulent boundary layer interactions. Both Reynolds averaged Navier-Stokes (RANS) and hybrid large-eddy / Reynolds-averaged Navier-Stokes (LES/RANS) turbulence closures are used with the IB technique. The approach is validated by comparing RANS and hybrid LES/RANS solutions obtained using the IB technique with RANS solutions obtained using a body-fitted mesh and with experimental laser Doppler anemometry (LDA) data collected at Cambridge University for Mach 2.5 flow over a single micro VG. Simulations of an impinging oblique shock / boundary layer interaction at Mach 2.5 with and without micro VG flow control are also performed, considering a.) the development of the entire flow in the wind tunnel using a RANS model and b.) an idealized, nominally two-dimensional interaction using both the RANS and the LES/RANS models Comparisons are made with experimental LDA data and surface pressure measurements from Cambridge University, and an analysis of the flow structure is performed. The results show that three-dimensional effects initiated by the interaction of the oblique shock with the sidewall boundary layers significantly influence the flow patterns in the actual experiment. The general features of the interactions with and without the micro VG array are predicted to good accord by the RANS / IB model. Results for the idealized interaction show the LES/RANS model captures a faster recovery of the separated boundary layer and a broader influence of the vortices generated by the micro VG array, compared with the RANS model.",
author = "Santanu Ghosh and Choi, {Jung Il} and Edwards, {Jack R.}",
year = "2008",
month = "1",
day = "1",
doi = "10.2514/6.2008-3728",
language = "English",
isbn = "9781563479427",
booktitle = "38th AIAA Fluid Dynamics Conference and Exhibit",
publisher = "American Institute of Aeronautics and Astronautics Inc.",

}

Ghosh, S, Choi, JI & Edwards, JR 2008, RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods. in 38th AIAA Fluid Dynamics Conference and Exhibit., 2008-3728, American Institute of Aeronautics and Astronautics Inc. https://doi.org/10.2514/6.2008-3728

RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods. / Ghosh, Santanu; Choi, Jung Il; Edwards, Jack R.

38th AIAA Fluid Dynamics Conference and Exhibit. American Institute of Aeronautics and Astronautics Inc., 2008. 2008-3728.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

TY - GEN

T1 - RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods

AU - Ghosh, Santanu

AU - Choi, Jung Il

AU - Edwards, Jack R.

PY - 2008/1/1

Y1 - 2008/1/1

N2 - This work presents an immersed boundary (IB) technique for compressible, turbulent flows and applies the technique to simulate the effects of micro vortex generators (micro VGs) in controlling oblique-shock / turbulent boundary layer interactions. Both Reynolds averaged Navier-Stokes (RANS) and hybrid large-eddy / Reynolds-averaged Navier-Stokes (LES/RANS) turbulence closures are used with the IB technique. The approach is validated by comparing RANS and hybrid LES/RANS solutions obtained using the IB technique with RANS solutions obtained using a body-fitted mesh and with experimental laser Doppler anemometry (LDA) data collected at Cambridge University for Mach 2.5 flow over a single micro VG. Simulations of an impinging oblique shock / boundary layer interaction at Mach 2.5 with and without micro VG flow control are also performed, considering a.) the development of the entire flow in the wind tunnel using a RANS model and b.) an idealized, nominally two-dimensional interaction using both the RANS and the LES/RANS models Comparisons are made with experimental LDA data and surface pressure measurements from Cambridge University, and an analysis of the flow structure is performed. The results show that three-dimensional effects initiated by the interaction of the oblique shock with the sidewall boundary layers significantly influence the flow patterns in the actual experiment. The general features of the interactions with and without the micro VG array are predicted to good accord by the RANS / IB model. Results for the idealized interaction show the LES/RANS model captures a faster recovery of the separated boundary layer and a broader influence of the vortices generated by the micro VG array, compared with the RANS model.

AB - This work presents an immersed boundary (IB) technique for compressible, turbulent flows and applies the technique to simulate the effects of micro vortex generators (micro VGs) in controlling oblique-shock / turbulent boundary layer interactions. Both Reynolds averaged Navier-Stokes (RANS) and hybrid large-eddy / Reynolds-averaged Navier-Stokes (LES/RANS) turbulence closures are used with the IB technique. The approach is validated by comparing RANS and hybrid LES/RANS solutions obtained using the IB technique with RANS solutions obtained using a body-fitted mesh and with experimental laser Doppler anemometry (LDA) data collected at Cambridge University for Mach 2.5 flow over a single micro VG. Simulations of an impinging oblique shock / boundary layer interaction at Mach 2.5 with and without micro VG flow control are also performed, considering a.) the development of the entire flow in the wind tunnel using a RANS model and b.) an idealized, nominally two-dimensional interaction using both the RANS and the LES/RANS models Comparisons are made with experimental LDA data and surface pressure measurements from Cambridge University, and an analysis of the flow structure is performed. The results show that three-dimensional effects initiated by the interaction of the oblique shock with the sidewall boundary layers significantly influence the flow patterns in the actual experiment. The general features of the interactions with and without the micro VG array are predicted to good accord by the RANS / IB model. Results for the idealized interaction show the LES/RANS model captures a faster recovery of the separated boundary layer and a broader influence of the vortices generated by the micro VG array, compared with the RANS model.

UR - http://www.scopus.com/inward/record.url?scp=78049516570&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78049516570&partnerID=8YFLogxK

U2 - 10.2514/6.2008-3728

DO - 10.2514/6.2008-3728

M3 - Conference contribution

SN - 9781563479427

BT - 38th AIAA Fluid Dynamics Conference and Exhibit

PB - American Institute of Aeronautics and Astronautics Inc.

ER -

Ghosh S, Choi JI, Edwards JR. RANS and hybrid LES/RANS simulations of the effects of micro vortex generators using immersed boundary methods. In 38th AIAA Fluid Dynamics Conference and Exhibit. American Institute of Aeronautics and Astronautics Inc. 2008. 2008-3728 https://doi.org/10.2514/6.2008-3728