Multiscale research in the Environmental and Applied Fluid Dynamics Department of the von Karman Institute (VKI), located in Belgium, will be presented, focusing on long-standing collaboration with the TU/e.

Standard Rainbow Thermometry measures the temperature of a single droplet, illuminated by a laser beam; a Ph.D thesis has been defended at TU/e in 1997 on this topic. Global Rainbow Thermometry has been invented in 1999 and measures the global temperature of an ensemble of droplets. This technique is applied to spray combustion and airborne measurements.

By putting a thin layer of sand on the floor of a city model at scale +/-1:300, installed in the VKI Atmospheric Boundary Layer Wind Tunnel, pedestrian wind comfort in the built environment can be studied in a visual manner. Comparison with Laser-Doppler Velocimetry, Irwin probes and Particle Image Velocimetry (PIV) establishes confidence in the use of sand erosion patterns for this purpose. A Ph.D thesis has been defended in 2006 at TU/e. Sand is also used for wind tunnel research on snow drifting in Antarctica and dune formation in Zuid-Holland.

 PIV has been invented in 1980 at VKI and has been adapted to the needs of many different applications. A multiscale approach has recently been developed in collaboration with TU/e. Both smoke particles and smoke structures can be tracked, depending on the scale of the studied phenomenon, simultaneously with smoke concentration measurements, for application to fire safety research.