caa a22 4500 606197028 CHVBK 20210128100927.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s00348-014-1891-5 doi (NATIONALLICENCE)springer-10.1007/s00348-014-1891-5 A PIV measurement of the natural transition of a natural convection boundary layer [Elektronische Daten] [Yongling Zhao, Chengwang Lei, John Patterson] A natural convection boundary layer undergoing natural transition to turbulence is investigated by particle image velocimetry (PIV) measurements for the first time. The boundary layer adjacent to an isothermally heated plate immersed in water is subjected to environmental noise, the transition of which is therefore regarded as a natural transition. Distinct stripe-like flow structures characterising the natural transition of the natural convection boundary layer are visualised for the first time by the PIV experiments. The spatial wavenumber and the frequency of the flow structures are further quantified by applying a two-dimensional Fourier transform to time series of the flow properties. A distinct transitional regime in the boundary layer is noted, in which the three-dimensionality of the flow grows exponentially in the streamwise direction. The characteristic frequency of the natural convection boundary layer is also obtained from the PIV measurements, which agrees well with a theoretical prediction reported previously. Springer-Verlag Berlin Heidelberg, 2014 Zhao Yongling School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut Lei Chengwang School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut Patterson John School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut Experiments in Fluids Springer Berlin Heidelberg 56/1(2015-01-01), 1-10 0723-4864 56:1<1 2015 56 348 https://doi.org/10.1007/s00348-014-1891-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-014-1891-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zhao Yongling School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Lei Chengwang School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Patterson John School of Civil Engineering, The University of Sydney, 2006, Sydney, NSW, Australia aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/1(2015-01-01), 1-10 0723-4864 56:1<1 2015 56 348