TY - JOUR
T1 - Numerical study of compressibility effects on the dynamic stall flow mechanism
AU - Pu, Xiang
AU - Liao, Binlong
AU - He, Guosheng
N1 - Publisher Copyright:
© 2025
PY - 2026/1
Y1 - 2026/1
N2 - The leading-edge vortex (LEV) and shock-induced vortex are the dominant mechanisms of inducing dynamic stall. As compressibility increases, there is a significant competitive relationship between these two mechanisms. This current works uses two dynamic stall onset criteria including the maximum magnitudes of the leading-edge suction parameter (LESPmax) and boundary enstrophy flux (|BEF|max) to further explore the competitive relationship between the two mechanisms on the occurrence of dynamic stalls when compressibility changes from mild to severe compressible regimes. By the numerical method, the results are obtained using improved delayed detached eddy simulation (IDDES) for a National Advisory Committee for Aeronautics (NACA) 0012 airfoil at Reynolds number (Rec) between 5 × 106∼1 × 107 and freestream Mach numbers (Ma∞) between 0.3–0.7. It is revealed that when Ma∞ is less than 0.4, the effect of compressibility is limited to the leading edge area, with the increase of compressibility LEV appears earlier which then leads to earlier dynamic stall, the LEV is the dominant factor inducing dynamic stall, the two criteria (LESPmax and |BEF|max) can predict the onset of dynamic stall. When Ma∞ is around 0.5, a fairly strong shock wave appears downstream of the leading edge area, in this scenario both the shock wave induced separation and the LEV are present, and the former is generated slightly earlier than the latter. Although the contribution of the leading-edge separation and shock induced separation are comparable according to the quantitative value of localized BEF, the shock wave seems to induce the formation of the early dynamic stall vortex (DSV), the two criteria are still considered usable to predict the stall onset. When Ma∞ is larger than 0.6, the shock wave dominates the formation of the initial DSV, the location of initial DSV generated is away from the leading edge area, and the two criteria are no longer applicable because of the effects of the strong shock wave.
AB - The leading-edge vortex (LEV) and shock-induced vortex are the dominant mechanisms of inducing dynamic stall. As compressibility increases, there is a significant competitive relationship between these two mechanisms. This current works uses two dynamic stall onset criteria including the maximum magnitudes of the leading-edge suction parameter (LESPmax) and boundary enstrophy flux (|BEF|max) to further explore the competitive relationship between the two mechanisms on the occurrence of dynamic stalls when compressibility changes from mild to severe compressible regimes. By the numerical method, the results are obtained using improved delayed detached eddy simulation (IDDES) for a National Advisory Committee for Aeronautics (NACA) 0012 airfoil at Reynolds number (Rec) between 5 × 106∼1 × 107 and freestream Mach numbers (Ma∞) between 0.3–0.7. It is revealed that when Ma∞ is less than 0.4, the effect of compressibility is limited to the leading edge area, with the increase of compressibility LEV appears earlier which then leads to earlier dynamic stall, the LEV is the dominant factor inducing dynamic stall, the two criteria (LESPmax and |BEF|max) can predict the onset of dynamic stall. When Ma∞ is around 0.5, a fairly strong shock wave appears downstream of the leading edge area, in this scenario both the shock wave induced separation and the LEV are present, and the former is generated slightly earlier than the latter. Although the contribution of the leading-edge separation and shock induced separation are comparable according to the quantitative value of localized BEF, the shock wave seems to induce the formation of the early dynamic stall vortex (DSV), the two criteria are still considered usable to predict the stall onset. When Ma∞ is larger than 0.6, the shock wave dominates the formation of the initial DSV, the location of initial DSV generated is away from the leading edge area, and the two criteria are no longer applicable because of the effects of the strong shock wave.
KW - Dynamic stall criteria
KW - IDDES
KW - LEV
KW - Shock-Induced Separation
UR - https://www.scopus.com/pages/publications/105013520871
U2 - 10.1016/j.ast.2025.110664
DO - 10.1016/j.ast.2025.110664
M3 - Article
AN - SCOPUS:105013520871
SN - 1270-9638
VL - 168
JO - Aerospace Science and Technology
JF - Aerospace Science and Technology
M1 - 110664
ER -