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Research Papers: Flows in Complex Systems

# Large Eddy Simulation of Coflow Jet Airfoil at High Angle of Attack

[+] Author and Article Information
Hong-Sik Im

Mem. ASME

Ge-Cheng Zha

Professor
e-mail: gzha@miami.edu

Bertrand P. E. Dano

Mem. ASME
Dept. of Mechanical and Aerospace Engineering,
University of Miami,
Coral Gables, FL 33124

1Currently at Honeywell, Torrance CA 90505.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received April 15, 2013; final manuscript received September 6, 2013; published online November 12, 2013. Assoc. Editor: Zvi Rusak.

J. Fluids Eng 136(2), 021101 (Nov 12, 2013) (10 pages) Paper No: FE-13-1240; doi: 10.1115/1.4025649 History: Received April 15, 2013; Revised September 06, 2013

## Abstract

Large eddy simulation (LES) is conducted to investigate coflow jet (CFJ) airfoil flows at high angle of attack (AOA). The Smagorinsky model with Van Driest damping is employed to resolve the subgrid-scale stress. The fifth-order weighted essentially non-oscillatory (WENO) scheme is used for reconstruction of the inviscid flux and the fourth-order central differencing for the viscous flux. The LES results at an AOA of $0 deg$, $12 deg$, $25 deg$, and $30 deg$ with momentum coefficients of $Cμ$= 0.15 and 0.08 are compared with the experiment to understand the flow structure of the jet mixing and flow separation. The quantitative prediction of lift and drag and qualitative prediction of vortex structures are in good agreement with experiment.

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## Figures

Fig. 1

CFJ airfoil concept

Fig. 2

LES mesh for the CFJ airfoil at 30 deg AOA, total mesh = 7,913,835, h(span) = 0.15 C(chord)

Fig. 3

LES mesh around the CFJ airfoil at 30 deg AOA

Fig. 4

LES mesh on the suction surface of the CFJ airfoil

Fig. 5

Mass flow rate at injection and suction slot of the CFJ airfoil predicted by LES at AOA of 25 deg for Cμ = 0.15, Re = 1.19179×105, M = 0.05

Fig. 6

Predicted lift(CL) coefficients of the CFJ airfoil at AOA of 0 deg, 12 deg, 25 deg, 30 deg; Re = 1.19179×105, M = 0.05

Fig. 7

Predicted drag(CD) coefficients of the CFJ airfoil at AOA of 0 deg, 12 deg, 25 deg, 30 deg; Re = 1.19179×105, M = 0.05

Fig. 8

Instantaneous entropy (ΔS/R = γ/1-γlnTt/Tt∞-lnPt/Pt∞) of the CFJ airfoil for Cμ = 0.15 at AOA of 0 deg, 12 deg, 25 deg, 30 deg; Re = 1.19179×105, M = 0.05

Fig. 9

Instantaneous smoke visualization of the CFJ airfoil by experiment; AOA = 30 deg, Cμ = 0.15 (bottom), Re = 1.19179×105, M = 0.05

Fig. 10

Instantaneous axial velocity (U) at axial plane AB¯ of the CFJ airfoil for Cμ = 0.15, Re = 1.19179×105, M = 0.05

Fig. 11

Instantaneous CFJ stalled flows contoured by axial velocity (U) for Cμ = 0.15, Re = 1.19179×105, M = 0.05; AOA = 25 deg (top), AOA = 30 deg (bottom)

Fig. 12

Instantaneous vorticity near the injection slot of the CFJ airfoil at AOA = 30 deg predicted by LES; Cμ = 0.08 (top), Cμ = 0.15 (bottom), Re = 1.19179×105, M = 0.05

Fig. 13

Instantaneous CFJ stalled flows contoured by velocity magnitude (Vm) for Cmu = 0.08 (top), Cmu = 0.15 (bottom); AOA = 30 deg, Re = 1.19179×105, M = 0.05

Fig. 14

Time average velocity (m/s) field of the CFJ airfoil at AOA = 30 deg for Cμ = 0.15 by the experiment; Re = 1.19179×105, M = 0.05

Fig. 15

Contours of velocity magnitude and streamlines of the CFJ airfoil for Cμ = 0.15, Re = 1.19179×105, M = 0.05 predicted by LES; AOA = 30 deg, time averaged(top), instantaneous(bottom)

Fig. 16

Instantaneous streamlines indicating mixing of the outer shear flow with the attached coflow jet predicted by LES; AOA = 30 deg, Cmu = 0.08 (top), Cmu = 0.15 (bottom), Re = 1.19179×105, M = 0.05

Fig. 17

Reynolds stress of the CFJ airfoil at 30 deg AOA, Re = 1.19179×105, M = 0.05 predicted by LES; streamwise (top), shear (middle), lateral (bottom)

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