Lift characteristics of two tandem airfoils in the globally unstable wake of a heated cylinder

Zhai，Xiangyu1; Yin，Bo1; Karimi，Nader2,3; Gupta，Vikrant4; Li，Larry K.B.1; Guan，Yu1; Ao，Wen5

2020

10.1007/s10973-020-10358-x

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY   影响因子和分区

1388-6150

1588-2926

In this numerical study, we use two-dimensional scale-adaptive simulations to investigate the lift characteristics of two tandem airfoils in the globally unstable wake of a cylinder at a Reynolds number of 10, with and without cylinder heating. Both airfoils have NACA 0012 profiles and are at the same angle of attack (α = 10°), implying zero decalage. We find that the lift characteristics of both airfoils depend strongly on the streamwise distance (X) between the trailing point of the cylinder and the leading edge of the fore airfoil. At the conditions of this study (1 ≤ X/D ≤ 5, where D is the cylinder diameter), both airfoils experience periodic limit-cycle oscillations in their lift coefficients (C) at the same frequency. However, when X/D < 3, abrupt decreases occur in both the C amplitude of the fore airfoil and the C oscillation frequency of both airfoils. We attribute these decreases to the fore airfoil entering the wavemaker region of the self-excited cylinder wake and altering its global instability properties. Heating the cylinder to a temperature above that of the free-stream leads to monotonic decreases in the oscillation frequency and amplitude of C for both airfoils. For the purpose of harvesting the maximum energy from two tandem airfoils behind a cylinder, our findings suggest that (i) the airfoils should be positioned as close as possible to the cylinder without disrupting the wavemaker of the globally unstable wake and (ii) the cylinder should be prevented from heating up.

Aerodynamics Computational fluid dynamics Flow instability Global instability

SCI ; EI

英语

其他

Thermodynamics ; Chemistry

Thermodynamics ; Chemistry, Analytical ; Chemistry, Physical

WOS:000584998300013

SPRINGER

20204409439285

Angle of attack ; Airfoils ; Cylinders (shapes) ; Reynolds number ; Wakes ; Lift

Fluid Flow, General:631.1 ; Aerodynamics, General:651.1 ; Aircraft, General:652.1 ; Computer Applications:723.5 ; Mechanics:931.1

CHEMISTRY

2-s2.0-85094662852

Scopus

1.Department of Mechanical and Aerospace Engineering,The Hong Kong University of Science and Technology,Clear Water Bay,Hong Kong
2.School of Engineering and Computer Science,Queen Mary University of London,Mile End,E1 4NS,United Kingdom
3.James Watt School of Engineering,University of Glasgow,Glasgow,G12 8QQ,United Kingdom
4.Guangdong Provincial Key Laboratory of Turbulence Research and Applications,Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,China
5.Science and Technology on Combustion,Internal Flow and Thermo-Structure Laboratory,Northwestern Polytechnical University,Xi’an,710072,China

Zhai，Xiangyu,Yin，Bo,Karimi，Nader,et al. Lift characteristics of two tandem airfoils in the globally unstable wake of a heated cylinder[J]. JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY,2020,145:2081-2093.

Zhai，Xiangyu.,Yin，Bo.,Karimi，Nader.,Gupta，Vikrant.,Li，Larry K.B..,...&Ao，Wen.(2020).Lift characteristics of two tandem airfoils in the globally unstable wake of a heated cylinder.JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY,145,2081-2093.

Zhai，Xiangyu,et al."Lift characteristics of two tandem airfoils in the globally unstable wake of a heated cylinder".JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 145(2020):2081-2093.