Aerodynamic Effects of Uniform Blowing and Suction on a NACA4412 Airfoil

Abstract

We carried out high-fidelity large-eddy simulations to investigate the effects of uniform blowing and uniform suction on the aerodynamic efficiency of a NACA4412 airfoil at the moderate Reynolds number based on chord length and incoming velocity of Re c = 200,000 . We found that uniform blowing applied at the suction side reduces the aerodynamics efficiency, while uniform suction increases it. This result is due to the combined impact of blowing and suction on skin friction, pressure drag and lift. When applied to the pressure side, uniform blowing improves aerodynamic efficiency. The Reynoldsnumber dependence of the relative contributions of pressure and friction to the total drag for the reference case is analysed via Reynolds-averaged Navier-Stokes simulations up to Re c = 10,000,000 . The results suggest that our conclusions on the control effect can tentatively be extended to a broader range of Reynolds numbers.

Investigation of Blowing and Suction for Turbulent Flow Control on Airfoils

“…In the present work, RANS simulations are chosen as means to cover the large parameter space of our investigation with acceptable accuracy and relatively limited modeling effort. The correctness of the approach is verified whenever possible with the well-resolved LES data by Atzori et al [24].…”

“…A sharp trailing edge configuration is utilized for the simulations, which corresponds to the setup of the LES reference configuration [24]. The LES serves as validation case for the mesh-independence study (see Section IV), which is performed by varying the overall resolution as well as individual directional mesh settings such as wall-normal and wall-parallel spacing around C. For the present study a total of 42 meshes was used covering different and airfoil geometries.…”

“…This limits their use for the intended parameter study on airfoils to a small parameter set of single characteristic operating points, as e.g. provided by Atzori et al [24].…”

Turbulent drag reduction over curved walls

“…Owing to issue (ii), though, how to assess drag reduction in practical applications, often characterized by curved walls and/or non-uniform pressure gradients, remains an interesting open problem. For example, Atzori et al (2020) recently applied drag reduction (via uniform blowing and body-force damping of near-wall turbulent fluctuations) to a finite wing slab studied by direct numerical simulations (DNS) and highly resolved large eddy simulation (LES). Because of the complexity of the flow, however, the influence of curvature on the drag reduction effectiveness could not be singled out, as concurrent flow phenomena (like transition and separation) prevent a direct and quantitative comparison with flat-plate boundary layer or plane channel flow.…”

Numerical analysis of a 3-D printed porous trailing edge for broadband noise reduction

“…Following Kametani & Fukagata (2011) and Atzori et al. (2020), the reduction suggests that flow ejection from the porous medium is more evident near the solid–porous junction, which can be linked to the flow recirculation pattern near the solid–porous junction in figure 15. Further downstream, the flow suction and ejection processes become more balanced, and the increased wall shear is mainly caused by the stronger velocity gradient near the porous medium surface (Koh et al.…”