Aeropropulsive Performance Modelling of Over-The-Wing Propulsion at Incidence

A semi-emperical model is developed, able to capture the aeropropulsive performance characteristics of Over-The-Wing propellers at incidence. The model is based on an hypothesis on the interactions of the propeller- and wing-induced flow fields. Effects of these interactions on the both the thrust and lift are written in a form in which the...

Three-Dimensional Quantitative Flow Visualization Around a Thrust Reverser

Volumetric particle tracking velocimetry measurements are performed in a low-speed wind tunnel to study the flow around a 1:12-scale aircraft model with jet engines operating with thrust reversers. The engine jet and freestream flow velocity are varied to yield a jet to freestream velocity ratio of V_jet/V_∞ ranging from 1...

Correction: Aeropropulsive Performance Modelling of Over-The-Wing Propulsion at Incidence

Unsteady flow behaviour of multi-rotors in ground proximity

The unsteady flow behaviour of two side-by-side rotors in ground proximity is experimentally investigated. The rotors induce a velocity distribution interacting with the ground causing the radial expansion of the rotor wakes. In between the rotors, an interaction of the two wakes takes place, resulting in an upward flow similar to a fountain....

Aerodynamic Interactions of Side-by-Side Rotors in Ground Proximity

An experimental investigation is conducted to study the aerodynamic behavior of a two-rotor system in ground proximity. The counter-rotating rotors are placed side-by-side in the hovering condition. The time-averaged and unsteady flow behavior is studied when the rotor-to-rotor lateral distance and the distance between the rotors and the...

Thrust-Reverser Investigation by Large-Scale 3D PIV

Volumetric PIV measurements are performed to study the flow development around a 1:12 scale model of a thrust reverser in a low-speed wind tunnel. The thrust-reverser operates in a freestream flow of 3-5 m/s and with a jet to freestream velocity ratio Vjet/Vinf ranging from 1.5 to 6. Making use of sub-millimeter helium-filled soap bubbles, large...

The slip velocity of nearly neutrally buoyant tracers for large-scale PIV

The behaviour of nearly neutrally buoyant tracers is studied by means of experiments with helium-filled soap bubbles and numerical simulations. The current models used for estimating the slip velocity of heavy micro particles and neutrally buoyant particles are reviewed and extended to include the effect of unsteady forces and particle...

Soap bubbles for large-scale PIV in industrial wind tunnels

This work evaluates the use of helium-filled soap bubbles (HFSB) for Particle Image Velocimetry (PIV) measurements at high Reynolds numbers (up to 3.2 million) in aeronautics. The measurements are performed in the Low Speed Tunnel (LST) of the German-Dutch Wind Tunnels (DNW) using a high-lift airfoil in close-to-stall conditions up to 70 m/s....

Generation and control of helium-filled soap bubbles for PIV

The operating regimes of an orifice-type helium-filled soap bubbles (HFSB) generator are investigated for several combinations of air, helium and soap flow rates to establish the properties of the production process and the resulting tracers. The geometrical properties of the bubbles, the production regimes and the production rates are studied...

Generation and control of helium-filled soap bubbles for large-scale PIV

The operating regimes of an orifice-type helium-filled soap bubbles (HFSB) generator are investigated to characterize the properties of the resulting tracers. The geometrical properties of the bubbles as well as the production rate are studied with high-speed shadowgraphy. The weight of the tracers relative to the mass of displaced air is...

Helium-filled soap bubbles tracing fidelity in wall-bounded turbulence

The use of helium-filled soap bubbles (HFSB) as flow tracers for particle image velocimetry (PIV) and particle tracking velocimetry (PTV) to measure the properties of turbulent boundary layers is investigated in the velocity range from 30 to 50 m/s. The experiments correspond to momentum thickness-based Reynolds numbers of 3300 and 5100. A...

High-resolution PIV analysis of compressibility effects in turbulent jets

An investigation on the compressibility effects arising into the near field of turbulent jets operated at high Reynolds number at Mach numbers M=0.3, 0.9 and 1.1 (under-expanded regime) is carried out with two-components planar PIV experiments with high resolution cameras. The arrangement of the PIV system allows for mapping out the flow field...

3D organization of high-speed compressible jets by tomographic PIV

This work investigates the three dimensional organization of compressible jets at high-speed regime by tomographic particle image velocimetry (TOMO PIV). Experiments are conducted at Mach numbers 0.3, 0.9 and 1.1 (underexpanded regime) across the end of the potential core within a large cylindrical domain (1.6Dx8D, with D=22mm the jet diameter)....

3D organization of high-speed compressible jets by tomographic PIV

This work investigates the three dimensional organization of compressible jets at high-speed regime by tomographic particle image velocimetry (TOMO PIV). Experiments are conducted at Mach numbers 0.3, 0.9 and 1.1 (underexpanded regime) across the end of the potential core within a large cylindrical domain (1.6Dx8D, with D=22mm the jet diameter)....

On the use of Particle Image Velocimetry to predict trailing edge noise

The feasibility of aeroacoustic noise predictions based on Particle Image Velocimetry (PIV) measurements is studied. For this purpose, experiments are conducted on a sharp trailing edge (TE) flow developed along a flat plate at free stream velocity of 15m/s. The acoustic emissions were characterized in the NLR Small Anechoic Wind Tunnel (KAT) by...

Combined Particle Image Velocimetry and acoustic measurements on a rod-airfoil configuration: Pilot test of the FLOVIST project

High-resolution PIV analysis of compressibility effects in turbulent jets

An investigation on the compressibility effects arising into the near field of turbulent jets operated at high Reynolds number at Mach numbers M=0.3, 0.9 and 1.1 (under-expanded regime) is carried out with two-components planar PIV experiments with high resolution cameras. The arrangement of the PIV system allows for mapping out the flow field...