چکیده مقاله
This paper presents a numerical characterization of the NREL S822 airfoil at a low Reynolds number representative of small horizontal axis wind turbines approximately Re = 8 4 × 10⁴ Two angle of attack AOA ranges are considered to cover both attached and separated flow regimes: a pre stall sweep from about 4° to 10° and a post stall neighborhood angles from roughly 12° up to 18° The flow is modeled with incompressible RANS; pre stall cases use the SST k ω model with an empirical transition model, while post stall cases employ SST with unsteady RANS where needed for robustness in the presence of large separations A C type grid with fine near wall resolution target y ≈1 and second order numerical schemes is validated by grid convergence GCI studies Clean surface lift and drag polars and surface pressure distributions are compared with established S822 and low speed wind tunnel datasets Results show a near linear lift curve in the pre stall regime and a pronounced low drag laminar bucket, with minimum drag coefficient CD ≈ 0 007 0 009 at moderate lift coefficients The maximum aerodynamic efficiency lift to drag ratio L/D reaches about 60 65 at mild angles around α≈4°, CL ~0 5 , within the laminar bucket The pressure coefficient Cp x/c distributions indicate a gentle suction peak near the leading edge and a short laminar separation bubble that gradually enlarges and shifts aft as α increases toward stall Post stall computations exhibit the expected docile stall character of the S series airfoils—namely, a gradual CL reduction and a sharp CD rise—along with broad regions of separated flow on the suction surface Within the estimated numerical uncertainty via GCI , the trends are consistent with reference S822 measurements, supporting the use of the computed polars in blade element momentum BEM design and in selecting operating envelopes for small wind turbine rotors
کلیدواژهها
نویسندگان
Amir Reza Mamouri
Department of Mechanical Engineering, Technical and Vocational University TVU , Tehran, Iran
شیوه ارجاع
Mamouri, Amir Reza,1404,Numerical Assessment of Design Parameters on the S822 Airfoil at Low Reynolds Numbers,1st International & 7th National conference on Mechanical-civil engineering and advanced technologies,Esfarayen
ارائهشده در
مجموعه مقالات اولین کنفرانس بین المللی و هفتمین کنفرانس ملی مهندسی مکانیک، عمران و فناوری های پیشرفته19 آبان 1404 · اسفراین