The improved delayed detached-eddy simulation(IDDES) method is used to simulate the reverse flows past an NACA0012 airfoil at medium(10°) and large(30°) angles of attack. The numerical results of the baselin...The improved delayed detached-eddy simulation(IDDES) method is used to simulate the reverse flows past an NACA0012 airfoil at medium(10°) and large(30°) angles of attack. The numerical results of the baseline configuration are compared with the available measurements. The effects of the undulating leading edge with four different amplitudes are compared and analyzed at angle of attack of 10°. Based on these analyses, the amplitude of A/C=0.04 yields the best performance. Compared with the uncontrolled case, the performances of the undulating leading edge are greatly improved with reducing of the aerodynamic fluctuations. Furthermore, the mechanisms of performance are explored by comparing the local flow structures near the undulations.展开更多
The delayed detached-eddy simulation with adaptive coefficient(DDES-AC)method is used to simulate the baseline and leading-edge undulation control of dynamic stall for the reverse flow past a finite-span wing with NAC...The delayed detached-eddy simulation with adaptive coefficient(DDES-AC)method is used to simulate the baseline and leading-edge undulation control of dynamic stall for the reverse flow past a finite-span wing with NACA0012 airfoil.The numerical results of the baseline configuration are compared with available measurements.DDES and DDES-AC perform differently when predicting the primary and secondary dynamic stalls.Overall,DDES-AC performs better owing to the decrease of grey area between the strong shear layer and the fully three-dimensional separated flow.Moreover,the effects of the undulating leading-edge on the forces,lift gradients,and instantaneous flow structures are explored.Compared with the uncontrolled case,the lift gradient in the primary dynamic stall is reduced from 18.4 to 8.5,and the secondary dynamic stall disappears.Therefore,periodic unsteady air-loads are also reduced.Additionally,the control mechanism of the wavy leading edge(WLE)is also investigated by comparison with the straight leading edge(SLE).No sudden breakdown of strong vortices is the main cause for WLE control.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.91852113,11772174,and 11672158)the National Key Research and Development Program of China(Grant No.2016YFA0401200)
文摘The improved delayed detached-eddy simulation(IDDES) method is used to simulate the reverse flows past an NACA0012 airfoil at medium(10°) and large(30°) angles of attack. The numerical results of the baseline configuration are compared with the available measurements. The effects of the undulating leading edge with four different amplitudes are compared and analyzed at angle of attack of 10°. Based on these analyses, the amplitude of A/C=0.04 yields the best performance. Compared with the uncontrolled case, the performances of the undulating leading edge are greatly improved with reducing of the aerodynamic fluctuations. Furthermore, the mechanisms of performance are explored by comparing the local flow structures near the undulations.
基金the National Natural Science Foundation of China(Grants 91852113 and 11772174,and 91952302),National Key Project(Grant GJXM92579)the National Key R&D Program of China(Grant 2019YFA0405302)the authors would like to express their gratitude to Tsinghua National Laboratory for Information Science and Tech no logy for computation resources.
文摘The delayed detached-eddy simulation with adaptive coefficient(DDES-AC)method is used to simulate the baseline and leading-edge undulation control of dynamic stall for the reverse flow past a finite-span wing with NACA0012 airfoil.The numerical results of the baseline configuration are compared with available measurements.DDES and DDES-AC perform differently when predicting the primary and secondary dynamic stalls.Overall,DDES-AC performs better owing to the decrease of grey area between the strong shear layer and the fully three-dimensional separated flow.Moreover,the effects of the undulating leading-edge on the forces,lift gradients,and instantaneous flow structures are explored.Compared with the uncontrolled case,the lift gradient in the primary dynamic stall is reduced from 18.4 to 8.5,and the secondary dynamic stall disappears.Therefore,periodic unsteady air-loads are also reduced.Additionally,the control mechanism of the wavy leading edge(WLE)is also investigated by comparison with the straight leading edge(SLE).No sudden breakdown of strong vortices is the main cause for WLE control.
