TY  - CHAP
A1  - Alexopoulos, Spiros
A1  - Hoffschmidt, Bernhard
A1  - Rau, Christoph
T1  - Comparison of steady-state and transient simulations for solar tower power plants with open-volumetric receiver
T2  - SolarPACES 2011 : concentrating solar power and chemical energy systems : 20 - 23 September, 2011, Granada, Spain
Y1  - 2011
CY  - Granada
ER  - 
TY  - JOUR
A1  - Hammer, Thorben
A1  - Quitter, Julius
A1  - Mayntz, Joscha
A1  - Bauschat, J.-Michael
A1  - Dahmann, Peter
A1  - Götten, Falk
A1  - Hille, Sebastian
A1  - Stumpf, Eike
T1  - Free fall drag estimation of small-scale multirotor unmanned aircraft systems using computational fluid dynamics and wind tunnel experiments
JF  - CEAS Aeronautical Journal
N2  - New European Union (EU) regulations for UAS operations require an operational risk analysis, which includes an estimation of the potential danger of the UAS crashing. A key parameter for the potential ground risk is the kinetic impact energy of the UAS. The kinetic energy depends on the impact velocity of the UAS and, therefore, on the aerodynamic drag and the weight during free fall. Hence, estimating the impact energy of a UAS requires an accurate drag estimation of the UAS in that state. The paper at hand presents the aerodynamic drag estimation of small-scale multirotor UAS. Multirotor UAS of various sizes and configurations were analysed with a fully unsteady Reynolds-averaged Navier–Stokes approach. These simulations included different velocities and various fuselage pitch angles of the UAS. The results were compared against force measurements performed in a subsonic wind tunnel and provided good consistency. Furthermore, the influence of the UAS`s fuselage pitch angle as well as the influence of fixed and free spinning propellers on the aerodynamic drag was analysed. Free spinning propellers may increase the drag by up to 110%, depending on the fuselage pitch angle. Increasing the fuselage pitch angle of the UAS lowers the drag by 40% up to 85%, depending on the UAS. The data presented in this paper allow for increased accuracy of ground risk assessments.
KW  - Multirotor UAS
KW  - Drag estimation
KW  - CFD
KW  - Wind tunnel experiments
KW  - Wind milling
Y1  - 2023
U6  - https://doi.org/10.1007/s13272-023-00702-w
SN  - 1869-5590 (Online)
SN  - 1869-5582 (Print)
N1  - Corresponding author: Thorben Hammer
PB  - Springer
CY  - Wien
ER  - 
TY  - CHAP
A1  - Alexopoulos, Spiros
A1  - Hoffschmidt, Bernhard
A1  - Rau, Christoph
A1  - Schmitz, M.
A1  - Schwarzbözl, P.
A1  - Pomp, Stefan
T1  - Simulation results for a hybridized operation of a gas turbine or a burner for a small solar tower power plant
T2  - SolarPACES 2010 : the CSP Conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France
Y1  - 2010
SP  - 82
EP  - 83
PB  - Soc. OSC
CY  - Saint Maur
ER  - 
TY  - CHAP
A1  - Ziolko, C.
A1  - Schmitz, M.
A1  - Sattler, Johannes Christoph
A1  - Khedim, Ahmed
A1  - Hoffschmidt, Bernhard
T1  - AlSol - the open volumetric receiver technology moves to Africa
T2  - SolarPACES 2010 : the CSP Conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France
Y1  - 2010
SP  - 93
EP  - 94
PB  - Soc. OSC
CY  - Saint Maur
ER  - 
TY  - CHAP
A1  - Alexopoulos, Spiros
A1  - Rau, Christoph
A1  - Hoffschmidt, Bernhard
A1  - Breitbach, Gerd
A1  - Latzke, Markus
T1  - Modelling and validation of a transient heat recovery steam generator of the solar tower power plant Juelich
T2  - Eurosun 2012 : Solar energy for a brighter future : conference proceedings : Rijeka, 18.-22.09.2012
Y1  - 2012
SP  - ID 97
CY  - Rijeka
ER  - 
TY  - CHAP
A1  - Bung, Daniel Bernhard
A1  - Sun, Q.
A1  - Meireles, I.
A1  - Matos, J.
A1  - Viseu, T.
T1  - USBR type III stilling basin performance for steep stepped spillways
T2  - Hydraulic structures into the 21st century : 4th IAHR International Symposium on Hydraulic Structures : 9.-11.2.2012, Porto
Y1  - 2012
SN  - 978-989-8509-01-7
ER  - 
TY  - CHAP
A1  - Kerpen, N. B.
A1  - Bung, Daniel Bernhard
A1  - Schlurmann, Torsten
T1  - Physical model investigations of pressure distributions next to ships passing through a lock
T2  - 5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010
Y1  - 2010
SN  - 978-7-5618-3671-2
SP  - 514
EP  - 519
PB  - Univ. Press
CY  - Tianjin
ER  - 
TY  - CHAP
A1  - Gogolin, C.
A1  - Carvalho, R.
A1  - Bung, Daniel Bernhard
A1  - Matos, J.
T1  - Experimental and numerical investigation of steady and unsteady flows in roughened channels with cross beams
T2  - 35th IAHR world congress : 8.-13.9.2013, Chengdu, China
Y1  - 2013
SP  - Artikelkennnummer: A10837C
PB  - Tsinghua Univ. Press
CY  - Beijing
ER  - 
TY  - CHAP
A1  - Oertel, Mario
A1  - Bung, Daniel Bernhard
T1  - Characteristics of cross-bar block ramp flows
T2  - Hydraulic structures into the 21st century : 4th IAHR International Symposium on Hydraulic Structures : 9.-11.2.2012, Porto
Y1  - 2012
SN  - 978-989-8509-01-7
ER  - 
TY  - CHAP
A1  - Schlurmann, Torsten
A1  - Bung, Daniel Bernhard
T1  - Experimental investigation of flow-induced radial gate vibrations at Lower Subansiri dam
T2  - Sixth Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : JOINT 2012 : 23.-29.9.2012, Keelung
Y1  - 2012
SP  - 7
EP  - 14
ER  -