On computational simulations of dynamic stall and its three-dimensional nature

Khalifa, Nabil M.; Rezaei, Amirsaman; Taha, Haithem E.

doi:10.1063/5.0170251

Cited by 8 publications

(3 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering that the main research object is the improvement of the dynamic stall characteristics of airfoils using a blowing jet, and the comparative analysis is on the difference in the performance changes in airfoils under aerodynamic actuation opening and closing conditions, it is reasonable to believe that the data analysis and conclusions obtained in this study are reliable. The dynamic stall flow studied is notoriously three-dimensional [59]; however, two-dimensional simulations can also accurately reflect the changes in aerodynamic curves during dynamic stall processes [60].…”

Section: Methods Validationmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Investigation on the Evolution Process of Different Vortex Structures and Distributed Blowing Control for Dynamic Stall Suppression of Rotor Airfoils

Li,

Yi,

et al. 2024

Actuators

View full text Add to dashboard Cite

The influencing characteristic for the evolution mechanism of a dynamic stall vortex structure and distributed blowing control on rotor airfoils was investigated. Based on the moving-embedded grid method, the finite volume scheme, and Roe’s FDS scheme, a simulation method for the unsteady flow field of a pitch-oscillating airfoil was established. The flow field of the NACA63-218 airfoil was calculated using Reynolds-averaged Navier–Stokes equations. The evolution processes of different vortex structures during dynamic stall and the principal controlled vortex mechanism affecting aerodynamic nonlinearity were analyzed based on the pressure contours Cp and Q of the flow field structure and the spatiotemporal evolution characteristics of the wall pressure distribution. The research indicated that dynamic stall vortices (DSVs) and shear layer vortices (SLVs) were the major sources of the increase in aerodynamic coefficients and the onset of nonlinear hysteresis. Building upon these findings, the concept of distributed blowing control for DSVs and shear layer vortices (SLVs) was introduced. A comparative analysis was conducted to assess the control effectiveness of dynamic stall with different blowing locations and blowing coefficients. The results indicated that distributed blowing control effectively inhibited the formation of DSVs and reduced the intensity of SLVs. This led to a significant decrease in the peak values of the drag and pitch moment coefficients and the disappearance of secondary peaks in the aerodynamic coefficients. Furthermore, an optimal blowing coefficient existed. When the suction coefficient Cμ exceeded 0.03, the effectiveness of the blowing control no longer showed a significant improvement. Finally, with a specific focus on the crucial motion parameters in dynamic stall, the characteristics of dynamic stall controlled by air blowing were investigated. The results showed that distributed air blowing control significantly reduced the peak pitching moment coefficient and drag coefficient. The peak pitching moment coefficient was reduced by 72%, the peak drag coefficient was reduced by 70%, and the lift coefficient hysteresis loop area decreased by 46%. Distributed blowing jet control effectively suppressed the dynamic stall characteristics of the airfoil, making the unsteady load changes gentler.

show abstract

Section: Methods Validationmentioning

confidence: 99%

“…study are reliable. The dynamic stall flow studied is notoriously three-dimensional [59]; however, two-dimensional simulations can also accurately reflect the changes in aerodynamic curves during dynamic stall processes [60].…”

Section: Methods Validationmentioning

confidence: 99%

Numerical Investigation on the Evolution Process of Different Vortex Structures and Distributed Blowing Control for Dynamic Stall Suppression of Rotor Airfoils

Li,

Yi,

et al. 2024

Actuators

View full text Add to dashboard Cite

show abstract

“…The IDDES method is employed for pitching airfoils. In contrast to RANS, IDDES cannot reach a grid and time step-independent solution as typically achieved by RANS solvers [32,33]. Nevertheless, the IDDES simulations of a pitching NACA 0012 airfoil are conducted using different grids and time steps.…”

Section: Pitching Naca 0012 Airfoilmentioning

confidence: 99%

Effects of Leading Edge Radius on Stall Characteristics of Rotor Airfoil

Jing,

Zhao,

Gao

et al. 2024

Aerospace

View full text Add to dashboard Cite

The effects of leading edge radius on the static and dynamic stall characteristics of rotor airfoils are investigated. Initially, a parametric airfoil (PARFOIL) method is employed to generate four morphed airfoils with different leading edge radii based on a NACA 0012 airfoil. Subsequently, the Reynolds-averaged Navier–Stokes (RANS) method is employed to simulate the aerodynamic characteristics of static airfoils, while the improved delayed detached-eddy simulation (IDDES) method is employed for pitching airfoils. The effectiveness and accuracy of the computational fluid dynamics (CFD) methods are demonstrated through favorable agreement between the numerical and experimental results. Finally, both the static and dynamic aerodynamic characteristics are simulated and analyzed for the airfoils with varying leading edge radii. Comparative analyses indicate that at low Mach numbers, the high adverse pressure gradient near the leading edge is the primary cause of leading edge separation and stall. A larger leading edge radius helps to reduce the suction pressure peak and adverse pressure gradients, thus delaying the leading edge separation and stall of airfoil. At high Mach numbers, the leading edge separation and stall are mainly induced by the shock wave. Variations in leading edge radius have minimal impacts on the high adverse pressure gradient induced by the shock wave, thus making the stall characteristics of airfoils almost unaffected at high Mach numbers.

show abstract