Eulerian and Lagrangian velocity measurements by means of image analysis
- 116 Downloads
The most common velocity measurement techniques, based on image analysis (PIV), determine the velocity by correlation of a portion of the digitised images and give an Eulerian description of the investigated field. Particle Tracking Velocimetry (PTV), based on the recognition of trajectories of seeding particles, only furnishes an Eulerian description provided that the trajectories are shorter than the characteristics scale of the phenomenon. If particles are tracked for a longer time, a Lagrangian description is obtained. Consequently, in order to successfully evaluate Lagrangian statistics, a long series of single-exposed images has to be acquired. PTV has been utilised in order to analyse different laboratory simulations of flow fields which assume a particular importance in environment applications such as in the flow in a porous media and in the convective atmospheric boundary layer.
Keywordsvelocity image analysis turbulence particle image velocimetry atmospheric boundary layer porous media
Unable to display preview. Download preview PDF.
- Dagan, G., Flow and Transport in Porous Formations, Springer-Verlag (1989)Google Scholar
- Einstein, A., On the Movement of Suspended Particles in Stationary Fluids Deduced from Molecular-Kinetic Theory of Heat (in German), Ann. Phys., 17, (1905), 539–560Google Scholar
- Hullin, J. P, and Salin, D., Experimental Study of Tracer Dispersion in Model and Natural Porous Media, Disorder and Mixing Convection, Diffusion and Reaction in Random Materials and Processes, Nato ASI Series: Series E, Vol. 152. (1988)Google Scholar
- Hunt, C. R., Kaimal, J. C. and Gaynor, J. E., Eddy Structure in the Convective Boundary Layer — New Measurements and New Conepts, Q.J.R. Met. Soc., 114, (1988), 827–870Google Scholar
- Levine, O., Zhang, D. and Neumann, S. P., Statistical Properties of Steady-state 3d Eulerian and Lagrangian Velocity Fields, Fall Meeting American Geophisical Union Published Ass. to EOS, (1992).Google Scholar
- Lorenço, L. M., Hisorical Background, Mathematical Tools in PIV, Processing Techniques, Lecture Series, v. Karman Institute of Fluid DynamicsGoogle Scholar
- Monin, A.S. and Yaglom, A.M., Statistical Fluid Mechanics, MIT Press, (1971), CambridgeGoogle Scholar
- Raffel, M. and Kompenhans, J., Theoretical and Experimental Aspects of PIV Recording Utilizing Photographic Film and Mechanical Image Shifting, Lecture Series, v. Karman Institute of Fluid Dynamics (1996)Google Scholar
- Virant, M. and Dracos, Th., An Application of 3D-PTV on the Measurement of Turbulent Quantities and Particle Dispersion in Turbulent Channel Flow, in Advances in turbulence VI, S. Gavrilakis et al. (eds), Kluwer Academic Publishers, The Netherlands (1996), 499–502Google Scholar