TY  - CHAP
A1  - Götten, Falk
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Gomez, Francisco
A1  - Bil, Cees
T1  - On the Applicability of Empirical Drag Estimation Methods for Unmanned Air Vehicle Design   Read More: https://arc.aiaa.org/doi/10.2514/6.2018-3192
T2  - 2018 Aviation Technology, Integration, and Operations Conference, AIAA AVIATION Forum
Y1  - 2018
U6  - http://dx.doi.org/10.2514/6.2018-3192
SN  - 1533-385X
N1  - AIAA 2018-3192
SP  - Article 3192
ER  - 
TY  - JOUR
A1  - Götten, Falk
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Gomez, Francisco
A1  - Bil, Cees
T1  - RANS Simulation Validation of a Small Sensor Turret for UAVs
JF  - Journal of Aerospace Engineering
N2  - Recent Unmanned Aerial Vehicle (UAV) design procedures rely on full aircraft steady-state Reynolds-Averaged-Navier-Stokes (RANS) analyses in early design stages. Small sensor turrets are included in such simulations, even though their aerodynamic properties show highly unsteady behavior. Very little is known about the effects of this approach on the simulation outcomes of small turrets. Therefore, the flow around a model turret at a Reynolds number of 47,400 is simulated with a steady-state RANS approach and compared to experimental data. Lift, drag, and surface pressure show good agreement with the experiment. The RANS model predicts the separation location too far downstream and shows a larger recirculation region aft of the body. Both characteristic arch and horseshoe vortex structures are visualized and qualitatively match the ones found by the experiment. The Reynolds number dependence of the drag coefficient follows the trend of a sphere within a distinct range. The outcomes indicate that a steady-state RANS model of a small sensor turret is able to give results that are useful for UAV engineering purposes but might not be suited for detailed insight into flow properties.
Y1  - 2019
U6  - http://dx.doi.org/10.1061/(ASCE)AS.1943-5525.0001055
SN  - 1943-5525
VL  - 32
IS  - 5
PB  - ASCE
CY  - New York
ER  - 
TY  - JOUR
A1  - Götten, Falk
A1  - Finger, Felix
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Gomez, Francisco
A1  - Bill, C.
T1  - On the flight performance impact of landing gear drag reduction methods for unmanned air vehicles
JF  - Deutscher Luft- und Raumfahrtkongress 2018
N2  - The flight performance impact of three different landing gear configurations on a small, fixed-wing UAV is analyzed with a combination of RANS CFD calculations and an incremental flight performance algorithm. A standard fixed landing gear configuration is taken as a baseline, while the influence of retracting the landing gear or applying streamlined fairings is investigated. A retraction leads to a significant parasite drag reduction, while also fairings promise large savings. The increase in lift-to-drag ratio is reduced at high lift coefficients due to the influence of induced drag. All configurations are tested on three different design missions with an incremental flight performance algorithm. A trade-off study is performed using the retracted or faired landing gear's weight increase as a variable. The analysis reveals only small mission performance gains as the aerodynamic improvements are negated by weight penalties. A new workflow for decision-making is presented that allows to estimate if a change in landing gear configuration is beneficial for a small UAV.
Y1  - 2018
U6  - http://dx.doi.org/10.25967/480058
PB  - DGLR
CY  - Bonn
ER  -