A scaling analysis for turbulent shock-wave/boundary-layer interactions

A model based on mass conservation properties is developed for shock-wave/boundarylayer interactions (SWBLIs), aimed at reconciling the observed great diversity in flow organization documented in the literature, induced by variations in interaction geometry and aerodynamic conditions. It is the basis for a scaling approach for the interaction...

Beyond Classical Upscaling: Integrated Aeroservoelastic Design and Optimization of Large Offshore Wind Turbines

Issues related to environmental concern and fossil fuel exhaustion has made wind energy the most widely accepted renewable energy resource. However, there are still several challenges to be solved such as the integrated design of wind turbines, aeroelastic response and stability prediction, grid integration, offshore resource assessment and...

Influence of Nonlinear Irregular Waves on the Fatigue Loads of an Offshore Wind Turbine

In order to make offshore wind power a cost effective solution that can compete with the traditional fossil energy sources, cost reductions on the expensive offshore support structures are required. One way to achieve this, is to reduce the uncertainty in wave load calculations by using a more advanced model for wave kinematics. As offshore wind...

Counter-hairpin vortices in the turbulent wake of a sharp trailing edge

Wing flexibility effects in clap-and-fling

The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water tank by use of a single wing model and a mirror plate to...

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...

Analysis of tail effects in flapping flight

Numerical simulations have been performed to examine the interference effects between an upstream flapping airfoil and a downstream stationary airfoil in a tandem configuration at a Reynolds number of 1000, which is around the regime of small flapping micro aerial vehicles. The objective is to investigate the effect of the distance of the tail...

Can wind lidars measure turbulence?

Modeling of the systematic errors in the second-order moments of wind speeds measured by continuouswave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model captures the effect of volume illumination and conical scanning. The predictions are compared with the...

The aero-acoustic resonance behavior of partially covered slender cavities

The present investigation focuses on the aero-acoustic resonance of cavities with a width much larger than their length or depth and partially covered, as often encountered in automotive door gaps. The cavities are under influence of a low Mach number flow with a relatively thick boundary layer. Under certain conditions, these cavities can...

Investigation of the unsteadiness of a shock-reflection interaction with time-resolved particle image velocimetry

The spatio-temporal dynamics of an impinging shock/boundary layer interaction atMach 2 and under incipient separation conditions, has been investigated experimentally by means of high-speed particle image velocimetry (PIV). The available PIV acquisition rate of up to 20 kHz permits a time-resolved characterization of the interaction. The...

Eulerian and Lagrangian views of a turbulent boundary layer flow using time-resolved tomographic PIV

Coherent structures and their time evolution in the logarithmic region of a turbulent boundary layer investigated by means of 3D space–time correlations and time-dependent conditional averaging techniques are the focuses of the present paper. Experiments have been performed in the water tunnel at TU Delft measuring the particle motion within a...

Lagrangian and Eulerian pressure field evaluation of rod-airfoil flow from time-resolved tomographic PIV

This work investigates the rod-airfoil air flow by time-resolved Tomographic Particle Image Velocimetry (TR-TOMO PIV) in thin-light volume configuration. Experiments are performed at the region close to the leading edge of a NACA0012 airfoil embedded in the von Karman wake of a cylindrical rod. The 3D velocity field measured at 5 kHz is used to...