The geometric effects of Coanda trailing edges on the aerodynamic performance of an airfoil are numerically evaluated for a range of different freestream Mach numbers and momentum coefficients. A Circulation control (CC) airfoil with a circular trailing edge (ACTE) proves to have better control effectiveness at low subsonic freestream speeds (Mach = 0.1). A CC airfoil having an elliptic trailing edge (AETE) outperforms the ACTE at high subsonic flow conditions. The occurrence of Cμ-stall for the AETE is greatly postponed, and meanwhile the maximum net lift coefficient increment achieved for the AETE (ΔCL = 0.51) is slightly higher than that of the ACTE (ΔCL = 0.50) at Mach 0.6. Compared to the ACTE, the AETE is found to have better control consistency at different operating velocities and better control stability when the Coanda jet is supersonic. Through careful consideration of the aerodynamic performance and the control effects, the most appropriate axial ratio for an AETE ellipse is within the interval from 1.5 to 2. Finally, the flow field instability phenomenon and the jet detachment induced by the supersonic Coanda jet are investigated. A self-sustained shock-wave instability phenomenon without jet detachment is first observed in this paper.
FrithSWoodN. Effect of trailing edge geometry on a circulation control delta wing. In: 21st AIAA applied aerodynamics conference, Orlando, FL, USA, 23–26 June 2003, AIAA paper no. 2003-3797.
2.
AhujaKKSankarLNEnglarRJ, et al.Application of circulation control technology to airframe noise reduction. Report for the Georgia Institute of Technology, Aerospace and Acoustics Technologies Branch, Report no. GTRI-A5928/2003-1, 2003.
3.
AbramsonJ. The low-speed characteristics of a 15-percent quasi-elliptical circulation control airfoil with distributed camber. Report for the David W. Taylor Naval Ship R&D Center Aviation and Surface Effects Department, Report no. DTNSRDC/ASED-79/07, 1979.
4.
PatersonEGBakerWJKunzRF, et al.RANS and detached-eddy simulation of the NCCR airfoil. In: 2004Users group conference (DOD_UGC’04), Williamsburg, VA, USA, 2004, pp. 112-122. New York: IEEE.
5.
WarsopCCrowtherWJ. Fluidic flow control effectors for flight control. AIAA J2018; 56: 3808–3824.
6.
NovakCCorneliusKRoadsR. Experimental investigations of the circular wall jet on a circulation control airfoil. In: 25th AIAA Aerospace sciences meeting, Reno, NV, USA, 24-26 March 1987, AIAA paper no. 1987-2155.
7.
EnglarRJHemmerlyRATaylorDW, et al.Design of the circulation control wing STOL demonstrator aircraft. J Aircraft1981; 18: 51–58.
8.
EnglarRJ. Two-dimensional transonic wind tunnel tests of three 15-percent thick circulation control airfoils. Report for the David W. Taylor Naval Ship R&D Center Aviation and Surface Effects Department, Report no. TN-AL-182, 1971.
9.
EnglarRJ. Development of the A-6/circulation control wing flight demonstrator configuration. Report for the David W. Taylor Naval Ship R&D Center Aviation and Surface Effects Department, Report no. DTNSRDC/ASED-79/01, 1979.
10.
AlexanderMGAndersSGJohnsonSK, et al.Trailing edge blowing on a two-dimensional six-percent thick elliptical circulation control airfoil up to transonic conditions. Report for the NASA Langley Research Center, Report no. NASA/TM-2005-213545, L-19058, 2005.
11.
MichieSN. Design methodology for circulation control maneuver effectors. PhD Thesis, The University of Manchester, UK, 2008.
12.
Robertson-WelshB. On the influence of nozzle geometries on supersonic curved wall jets. PhD Thesis, The University of Manchester, UK, 2017.
13.
Llopis-PascualA. Supercritical Coanda jets for flight control effectors. PhD Thesis, The University of Manchester, UK, 2016.
14.
CagleC. A wind tunnel model to explore unsteady circulation control for general aviation applications. In: 22nd AIAA Aerodynamic measurement technology and ground testing conference, St. Louis, MS, USA, 24-26 June 2002, AIAA paper no. 2002-3240.
15.
BevilaquaPMLeeJD. Development of a nozzle to improve the turning of supersonic Coanda jets. Report for the Rockwell International North American Aircraft Division, Report no. NR80H-18, 1980.
16.
Gregory-SmithDGSeniorP. The effects of base steps and axisymmetry on supersonic jets over Coanda surfaces. Int J Heat Fluid Flow1994; 15: 291-298.
17.
CarpenterPWGreenPN. The aeroacoustics and aerodynamics of high-speed Coanda devices, part 1: conventional arrangement of exit nozzle and surface. J Sound Vibrat1997; 208: 777–801.
18.
AbramsonJRogersE. High-speed characteristics of circulation control airfoils. In: 21st Aerospace sciences meeting, Reno, NV, USA, 10–13 January 1983, AIAA paper no. 1983-265.
19.
WoodNNielsenJ. Circulation control airfoils-past, present, future. In: 23th Aerospace sciences meeting, Reno, NV, USA, 14–17 January 1985, AIAA paper no. 1985-2204.
20.
AlexanderMGAndersSGJohnsonSK. Trailing edge blowing on a two-dimensional six-percent thick elliptical circulation control airfoil up to transonic conditions. Report for the NASA Langley Research Center, Report no. NASA/TM-2005-213545, 2005.
21.
SchlechtRAndersSG. Parametric evaluation of thin, transonic circulation-control airfoils. In: 45th AIAA Aerospace sciences meeting and exhibit, Reno, NV, USA, 8–11 January 2007, AIAA paper no. 2007-2272.
22.
ForsterMSteijlR. Numerical simulation of transonic circulation control. In: 53th AIAA Aerospace sciences meeting, Kissimmee, FL, USA, 5–9 January 2015, AIAA paper no. 2015-1709.
23.
CoulurisGJSignorDPhillipsJ. Cruise-efficient short takeoff and landing (CESTOL): potential impact on air traffic operations. Report for the NASA Ames Research Center, Report no. NASA/CR-2010-216392, 2010.
24.
CookMVBuonannoAErbslöhSD. A circulation control actuator for flapless flight control. Aeronaut J2008; 112: 483–489.
25.
EnglarRJJonesGAllanB, et al.2-D circulation control airfoil benchmark experiments intended for CFD code validation. In: 47th AIAA Aerospace sciences meeting including the new horizons forum and aerospace exposition, Orlando, FL, USA, 5–8 January 2009, AIAA paper no. 2009-2902.
26.
EnglarRJ. Experimental investigation of the high velocity Coanda wall jet applied to bluff trailing edge circulation control airfoils. Report for the David W. Taylor Naval Ship R&D Center Aviation and Surface Effects Department, Report no. AERO-1213, 1975.
27.
JonesGVikenSWashburnA, et al.An active flow circulation controlled flap concept for general aviation aircraft applications. In: 1st Flow control conference, St. Louis, MS, USA, 24–26 June 2002, AIAA paper no. 2002-3157.
28.
LothJLFanucciJBRobertsSC. Flight performance of a circulation controlled STOL aircraft. J Aircraft1976; 13: 169–173.
29.
CurraoMDChoudhuryR. Hypersonic transitional shock wave boundary layer interaction on a flat plate. AIAA J2019; 61702: 1–16.
30.
ShihIPTehEJ. Reynolds-Averaged simulations of shock wave boundary layer interactions with bleed. In: 51st AIAA Aerospace sciences meeting including the new horizons forum and aerospace exposition, Grapevine, TX, USA, 7–10 January 2013, AIAA paper no. 2013-0423.
31.
McGowanGGopalarathnamA. Computational study of a circulation control airfoil using FLUENT. In: GregorySJRonaldDJ (eds) Applications of circulation control technologies. Reston: AIAA, 2006, p. 539.
32.
XuHY, et al.Active circulation control on the blunt trailing edge wind turbine airfoil. AIAA J2018; 56: 1–17.
33.
XuH-YDongQ-LQiaoC-L, et al.Flow control over the blunt trailing edge of wind turbine airfoils using circulation control. Energies2018; 11: 619.
34.
TijdemanHSeebassR. Transonic flow past oscillating airfoils. Annu Rev Fluid Mech1980; 12: 181–222.
35.
PearceyHH. Some effects of shock-induced separation of turbulent boundary layers in transonic flow past aerofoils. Report for the Aeronautical Research Council, Report no. ARC R&M-3108, June 1955.
36.
PearceyHH. A method for the prediction of the onset of buffeting and other separation effects from wind tunnel tests on rigid models. AGARD Report223, October 1958.
