Two state-of-the-art three-dimensional experimental methods ready for the research of turbulence

We present two novel experimental systems developed for turbulence research during the past 20 years. In its present form the experimental methods, namely multi-hot-cold-wire anemometry (MHCWA) and three-dimensional particle tracking velocimetry (3D-PTV), are shown to provide new aspects of turbulent flows, especially in the smallest scales. The unique capabilities of the systems are their three-dimensional access to the flow measurements and approach allowing for detailed investigation of spatial derivatives of fluctuating, turbulent velocity. Main principles of the two experimental methods are shown in the manuscript and new findings are briefly summarized. The two experimental systems have been extensively developed at the School of Mechanical Engineering of the Tel Aviv University.