Comparative assessment of pressure field reconstructions from particle image velocimetry measurements and Lagrangian particle tracking

A test case for pressure field reconstruction from particle image velocimetry (PIV) and Lagrangian particle tracking (LPT) has been developed by constructing a simulated experiment from a zonal detached eddy simulation for an axisymmetric base flow at Mach 0.7. The test case comprises sequences of four subsequent particle images (representing...

Comparative assessment of PIV-based pressure evaluation techniques applied to a transonic base flow

A test case for PIV-based pressure evaluation techniques has been developed by constructing a simulated experiment from a ZDES simulation for an axisymmetric base flow at Mach 0.7. The test case comprises sequences of four subsequent particle images (representing multi-pulse data) as well as continuous time-resolved data. Particle images were...

Dynamic pitching effect on a laminar separation bubble

The unsteady effect of a periodic pitching motion on the characteristic of a laminar separation bubble on the suction side of a SD7003 aerofoil is investigated by means of time-resolved planar and tomographic particle image velocimetry. The measurements provide information on the separation, transition and vortex roll-up onset as well as the...

Gliding Swifts Attain Laminar Flow over Rough Wings

Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1–2% of chord length on the upper surface—10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing...

Pressure from particle image velocimetry for convective flows: A Taylor’s hypothesis approach

Taylors hypothesis is often applied in turbulent flow analysis to map temporal information into spatial information. Recent efforts in deriving pressure from particle image velocimetry (PIV) have proposed multiple approaches, each with its own weakness and strength. Application of Taylors hypothesis allows us to counter the weakness of an...

Instantaneous planar pressure determination from particle image velocimetry

Forces on flapping or rotating wings, like flapping wings of micro air vehicles or blades of wind turbines are of great interest to engineers. To investigate the ways birds and insects fly, forces created by flapping wings are of importance to biologists. The pressure field, combined with the velocity field, gives a complete description of the ...

Instantaneous planar pressure determination from PIV in turbulent flow

This paper deals with the determination of instantaneous planar pressure fields from velocity data obtained by particle image velocimetry (PIV) in turbulent flow. The operating principles of pressure determination using a Eulerian or a Lagrangian approach are described together with theoretical considerations on its expected performance. These...

3, 2, 1, Launch!

It is important that young people who chose to pursue a degree in engineering stick with their choice. Unfortunately students often loose their motivation during their first year. This paper gives an example of how the Faculty of Aerospace Engineering of Delft University in The Netherlands manages to keep a large number of freshmen motivated and...

Aerodynamic Experiments on DelFly II: Unsteady Lift Enhancement

Particle image velocimetry measurements and simultaneous force measurements have been performed on the DelFly II flapping-wing MAV, to investigate the flow-field behavior and the aerodynamic forces generated. For flapping wing motion it is expected that both the clap and peel mechanism and the occurrence of a leading edge vortex during the...

Instantaneous planar pressure field determination based on time-resolved Stereo-PIV

Vortex wake investigation behind a wing-flap model with jet simulations

To get a better insight in the effect of jets on vortex development and decay, stereo-PIV measurements were performed in a towing tank behind a flapped aircraft model. The experimental data set yields the wake vortex behavior in a range that extends from the vortex formation stage up to the mid-field (approximately t* =2 corresponding to 100...

Instantaneous planar pressure field determination around a square-section cylinder based on time resolved stereo-PIV