Stereo Particle Image Velocimetry proves an important tool in a wide range of test campaigns


Report gives an overview of the use of Stereo Particle Image Velocimetry (PIV) at MARIN over the years.


PIV is an advanced, optical measuring tech- nique for obtaining 3D velocity information in a plane. The flow measurement with PIV is based on the measurements of the displace- ment (Δx) of a particle in a target plane between two successive light pulses with time delay (Δt). The flow is seeded with particles and the target plane is illuminated with a laser light sheet. Then the particle positions are recorded by two digital cameras.


Special image processing software analyses the movements of the group of particles in subsections of the PIV image using correlation techniques. By using two cameras in a stereoscopic arrangement the instantaneous three velocity components are derived in the measuring plane (see MARIN Report 98 for more details). We have conducted 26 test campaigns with the submerged stereo-PIV system since it became operational in 2009. These test campaigns were performed for an internal research study, external clients and the Joint Industry Projects Trust, Jili and Moonpool. Typical applications include propeller outflow, Energy Saving Devices and thruster inter- actions such as thruster-hull and thruster- thruster, amongst others.


Rink Hallmann r.hallmann@marin.nl


For the propeller outflow and Energy Saving Devices, high quality data (see figure) was obtained by triggering the PIV system for each propeller rotation to capture sufficient


recordings. Additionally, in the standard submerged towing tank setup, we have used the system in dedicated measurement setups for special flows. The flow inside the moonpool was measured by mounting the cameras and laser inside the vessel using transparent moonpool walls and illuminating the whole measurement plane with the laser and a well-positioned mirror to reflect the laser light. Breaking waves were measured successfully in a small wave research flume. A similar setup was used for measurements in the Cavitation Tunnel.


PIV has certainly proven to be an important tool to obtain detailed flow field information for various hydrodynamic topics. On top of this it can generate experimental data for the validation of numerical results (Computational Fluid Dynamics) today and in the future.


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