TY - JOUR A1 - Götten, Falk A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - Airfoil drag at low-to-medium reynolds numbers: A novel estimation method JF - AIAA Journal N2 - This paper presents a novel method for airfoil drag estimation at Reynolds numbers between 4×10⁵ and 4×10⁶. The novel method is based on a systematic study of 40 airfoils applying over 600 numerical simulations and considering natural transition. The influence of the airfoil thickness-to-chord ratio, camber, and freestream Reynolds number on both friction and pressure drag is analyzed in detail. Natural transition significantly affects drag characteristics and leads to distinct drag minima for different Reynolds numbers and thickness-to-chord ratios. The results of the systematic study are used to develop empirical correlations that can accurately predict an airfoil drag at low-lift conditions. The new approach estimates a transition location based on airfoil thickness-to-chord ratio, camber, and Reynolds number. It uses the transition location in a mixed laminar–turbulent skin-friction calculation, and corrects the skin-friction coefficient for separation effects. Pressure drag is estimated separately based on correlations of thickness-to-chord ratio, camber, and Reynolds number. The novel method shows excellent accuracy when compared with wind-tunnel measurements of multiple airfoils. It is easily integrable into existing aircraft design environments and is highly beneficial in the conceptual design stage. Y1 - 2020 U6 - http://dx.doi.org/10.2514/1.J058983 SN - 1533-385X VL - 58 IS - 7 SP - 2791 EP - 2805 PB - AIAA CY - Reston, Va. ER - TY - JOUR A1 - Götten, Falk A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - Aerodynamic Investigations of UAV Sensor Turrets - A Combined Wind-tunnel and CFD Approach JF - SciTech 2021, AIAA SciTech Forum, online, WW, Jan 11-15, 2021 Y1 - 2021 U6 - http://dx.doi.org/10.2514/6.2021-1535 SP - 1 EP - 12 PB - AIAA CY - Reston, Va. ER - TY - CHAP A1 - Geiben, Benedikt A1 - Götten, Falk A1 - Havermann, Marc T1 - Aerodynamic analysis of a winged sub-orbital spaceplane T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2020 Y1 - 2020 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Marino, Matthew A1 - Bil, Cees A1 - Havermann, Marc A1 - Braun, Carsten T1 - A review of guidelines and best practices for subsonic aerodynamic simulations using RANS CFD T2 - Asia-Pacific International Symposium on Aerospace Technology (APISAT), At Gold Coast, Australia, 04. - 06. Dezember 2019 Y1 - 2019 SN - 978-1-925627-40-4 ER - TY - CHAP A1 - Götten, Falk A1 - Finger, Felix A1 - Havermann, Marc A1 - Braun, Carsten A1 - Marino, Matthew A1 - Bil, Cees T1 - A highly automated method for simulating airfoil characteristics at low Reynolds number using a RANS - transition approach T2 - Deutscher Luft- und Raumfahrtkongress - DLRK 2019. Darmstadt, Germany Y1 - 2019 U6 - http://dx.doi.org/10.25967/490026 SP - 1 EP - 14 ER -