Many processes occur much faster than can be observed by the eye, such as the growth and collapse of cavitation on a propeller or the impact of a wave on a structure. When we use high-speed video we can watch such a process slowed down for careful study. At MARIN, high-speed video is applied using frame rates that are up to 200 higher than normal video. The high frame rate ensures that the details of the process are captured.

Particle Image Velocimetry is a method to determine the velocities in a fluid. The flow measurement with PIV is based on the measurements of the displacement (∆x) of a particle in a target plane between two successive light pulses with time delay (∆t). The flow is seeded with particles and the target plane is illuminated with a light sheet. The particle positions are recorded by two special 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.

The 6 component transducers can be used for measuring the omnidirectional propeller loads, while 5 component transducer can be used for measuring 2 blade forces and 3 blade moments. Combined with time synchronised high speed video recordings this can provide an insight in dynamic propeller loading phenomena.

MARIN performs measurements anywhere, any time around the globe. Find here a selection of the tools and instruments that we use.