CEAS Aeronautical Journal

, Volume 8, Issue 3, pp 441–460 | Cite as

Numerical and experimental investigations of the propeller characteristics of an electrically powered ultralight aircraft

  • M. StuhlpfarrerEmail author
  • A. Valero-Andreu
  • C. Breitsamter
Original Paper


The performance and efficiency of a propeller is crucial for electrically powered propulsion systems. Since the energy of the batteries is limited, it is important to develop propellers with high efficiency. Therefore, numerical and experimental investigations of the propeller characteristics are performed. The wind tunnel experiments are performed on a fuselage–propeller configuration. The electrical motor, batteries, and control units are designed to be integrated in the fuselage. Furthermore, force measurements are conducted to provide a data base for the validation of the numerical results. Two different numerical approaches are presented. First, the propeller is fully resolved by applying a rotational domain and a sliding mesh interface. Second, an actuator disk approach including blade element theory with a panel method one-way coupled with a boundary layer integration method is presented. The latter shall be used to reduce computational and mesh generation costs. The thrust, efficiency as well as pressure distribution and the flow field downstream of the propeller are analyzed. The obtained numerical results show a good agreement with the experimental data for the integral values over a wide operating range. Moreover, the results of the inter-method comparison of the two numerical approaches are in a good accordance regarding the local effects for the two highlighted operating points.


Propeller aerodynamics High-fidelity simulations Electric flight Actuator disk modeling 

List of symbols


Influence coefficient matrix


Number of propeller blades


Blade tip


Chord length


Drag coefficient


Skin friction coefficient


Lift coefficient


Pressure coefficient


Specific heat for constant pressure


Torque coefficient


Thrust coefficient


Drag force



\(F_{\varphi }\)

Circumferential force


Shape factor




Propeller advance ratio


Turbulence kinetic energy


Lift force


Variable for Thwaites’ model


Component of the moment


Mach number


Number of cells


Rounds per minute



\(p_{\text{in}} ,p_{\text{out}}\)

Pressure at inlet and outlet




Heat flux




Reynolds number


Source term component






Total temperature


Effective velocity

\(U_{\infty }\)

Free-stream velocity

\(u_{\infty } ,v_{\infty }\)

Free-stream velocity components


Velocity far downstream of the propeller plane

\(u_{\text{ind}} ,v_{\text{ind}}\)

Induced velocity components


Component of the velocity




Axial velocity


Relative velocity


Radial velocity

\(V_{\varphi }\)

Circumferential velocity


Cartesian coordinates

\(x,\varphi ,r\)

Cylindrical coordinates

\(y^{ + }\)

Dimensionless wall distance


Kinematic viscosity


Angle of attack


Density relaxation factor


Pressure relaxation factor


Turbulent kinetic energy relaxation factor


Momentum relaxation factor


Temperature relaxation factor

\(\alpha_{\nu t}\)

Turbulence eddy viscosity relaxation factor

\(\alpha_{\omega }\)

Turbulence eddy frequency relaxation factor


Boundary layer thickness


Displacement thickness


Vortex strength


Thermal conductivity


Variable for Thwaites’ model




Molecular viscosity


Local angle of incidence


Angle of incidence at 75 per cent of the blade span


Momentum thickness




Inflow angle




Turbulence eddy frequency



Blade element theory


Combined RANS/blade element theory approach


Combined RANS/blade element theory approach including the fuselage configuration in the wind tunnel test section


Reference blade pitch angle


Technical University of Munich


Chair of Aerodynamics and Fluid Mechanics


Unmanned aerial systems


URANS results for the calculations of the resolved propeller



The authors thank the Bavarian State Ministry of Economic Affairs and Media, Energy and Technology for funding the project EUROPAS under the Grant Agreement Number LABAY76A. Furthermore, the authors want to thank ANSYS for providing the flow simulation software. The authors gratefully acknowledge the Gauss Centre for Supercomputing e.V. ( for funding this project by providing computing time on the GCS Supercomputer SuperMUC at Leibniz Supercomputing Centre (LRZ,


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Copyright information

© Deutsches Zentrum für Luft- und Raumfahrt e.V. 2017

Authors and Affiliations

  • M. Stuhlpfarrer
    • 1
    Email author
  • A. Valero-Andreu
    • 1
  • C. Breitsamter
    • 1
  1. 1.Department of Mechanical Engineering, Chair of Aerodynamics and Fluid MechanicsTechnical University of MunichGarching bei MünchenGermany

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