Low-magnification particle positioning for 3D velocimetry applications

✍ Scribed by P Padilla Sosa; D Moreno; J.A Guerrero; M Funes-Gallanzi

• Book ID: 104159664
• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 432 KB
• Volume: 34
• Category: Article
• ISSN: 0030-3992
• DOI: 10.1016/s0030-3992(01)00096-2

✦ Synopsis

Three-dimensional (3D) position and velocity information can be extracted by directly analysing the scattering patterns in velocimetry imaging of seeding particles using real-time CCD cameras. A Fraunh ofer di raction simpliÿcation of generalised Lorenz-Mie theory is shown to yield a representative model of particle position, such that particle position can be approximately deduced from typical experimental particle images. Data are obtained by pattern-matching theoretical to experimental images using a Nelder-Mead algorithm, subject to digitisation considerations and the concept of "locales". In this way, information about the characteristics of positional error as a function of magniÿcation, pixel size, intensity resolution, and spatial resolution can be derived. This work shows that an optimum magniÿcation exists, beneath which error begins to increase drastically. A practical application is demonstrated. The theory, simulations and experimental veriÿcation of this basic problem are discussed.