Overview of stability and transition in external aerodynamics

The boundary layer along the fuselage, wings and tailplanes of aircraft will usually be laminar at the leading edge and will become unstable further downstream. Once the boundary layer has become unstable it will undergo transition to turbulence. Stability and transition can be considered as one of the most complex problems of fluid dynamics....

Definition, transformation-formulae and measurements of tipvane angles

Carried out within the Dutch Development Program for Wind Energy (NOW-2); by order of the Management Office for Energy Research PEO; financed by the Ministry of Economie Affairs.

Overview of turbulence models for external aerodynamics

An overview is given on the background of different turbulence models that can be used to compute boundary layers in external aerodynamics, such as for aircraft. The overview includes algebraic models (Cebeci-Smith, Baldwin-Lomax), a half-equation model (Johnson-King), two-equation models ( K-E-K-), and a differential Reynolds-stress model. The...

Aerodynamic analysis of the wing flexibility and the clap-and-peel motion of the hovering DelFly II

In this paper, the influence of wing flexibility and the 'clap-and-peel' motion (one versus two wings) on the upward (lifting) force in hover is studied. CFD simulations based on the ALE Navier-Stokes equations together with radial basis function mesh interpolation are used. For the 'clap-and-peel' motion an immersed symmetry plane is introduced...

The effect of particle image blur on the correlation map and velocity measurement in PIV

In PIV particle image blur is usually observed near fluid optical interfaces, i.e. shock waves, and thin flow structure with large density variations, e.g. shear layers and boundary layers. In such an environment the particle image is not only subject to blur, but is also displaced from its actual position due to refraction, which is denoted as...

Improving BEM-based Aerodynamic Models in Wind Turbine Design Codes

Prediction of a tail downwash, ground effect and minimum unstick speed of jet transport aircraft

A design tool has been developed to estimate the horizontal tail size of a jet transport aircraft during the preliminary design phase with regard to the minimum unstick requirement. The ground effect has been modelled analytically using lifting line theory. The minimum unstick manoeuvre has been simulated numerically and is embedded in the...

Vortex flow and Vortex breakdown above delta wing in high subsonic flow

The near wake of the VAWT: 2D and 3D views of the VAWT aerodynamics

The analysis, modeling and design of the lift-driven Vertical Axis Wind Turbine (VAWT) has challenged the wind energy community for many decades; this limited progress in knowledge has severely impaired the development of the VAWT, giving rise to the myth that the VAWT rotor is inherently inefficient (in comparison with the more conventional...

Tomographic particle image velocimetry and its application to turbulent boundary layers

Tomographic Particle Image Velocimetry is a new experimental method developed to study three-dimensional motion in turbulent flows. The technique is an extension of standard PIV and makes use of several simultaneous views of illuminated tracer particles and their three-dimensional reconstruction as a light intensity distribution by means of...

Aerodynamics of flapping-wing Micro-Air-Vehicle: An integrated experimental and numerical study

The interest in Micro Air Vehicles (MAVs) has stimulated continuous research activities, in view of their potential in civilian and military applications. An autonomous MAV with dedicated onboard sensors would be capable of executing mission in closed environments, such as surveillance, in door inspection in support of rescue operations and...

Applications of a discrete viscous adjoint method for aerodynamic shape optimisation of 3D configurations

Within the next few years, numerical shape optimisation based on high-fidelity methods is likely to play a strategic role in future aircraft design. In this context, suitable tools have to be developed for solving aerodynamic shape optimisation problems, and the adjoint approach—which allows fast and accurate evaluations of the gradients with...

Shaping up blunt bodies

Lorries are great for transporting goods, but their inferior aerodynamics means they get fewer kilometers a liter of fuel. Bad news indeed for the environment, and for hauliers purses. But according to researchers at Delft University of Technology, cones and wings attached to the rear end along with technical tricks suspended under the vehicle...

Drag reduction through a streamlined aerodynamic design process: Development and implementation of a methodology to accelerate the aerodynamic design process in the preliminary phase of car design

Continuous innovation is very important to stay competitive in today’s world. Automotive manufacturers are an excellent example of this evolution when looking to new vehicle concepts. But also behind the scene, they have to be innovative in order to be able to keep up this progression. Aerodynamics has a large influence on the total performance...

A numerical investigation into the aerodynamic characteristics of AeroCity

The Use of Dielectric Barrier Discharge Plasma Actuators for Low-Speed Flow Control

An Investigation of the Non-Linear 3D Flow Effects Relevant for Leading Edge Inflatable Kites

The kite power group at TU Delft is currently researching the use of leading edge inflatable (LEI) kites for use in power generation. A thorough understanding of the aeroelastics of these kites is paramount to the development of system simulation models and optimum kite and system designs. The current lack of understanding is therefore seen as a...

Influence of turbulence on the derivation of the drag from wake measurements