Study of two-phase Lagrangian autocorrelation functions in a mixing-layer flow

• Main Authors: Yu-Feng Huang, 黃裕峰
• Other Authors: Keh-Chin Chang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/75656886038013276853

碩士 === 國立成功大學 === 航空太空工程學系 === 88 === Turbulent dispersion of the dispersed-phase elements in two-phase flows can be performed by probabilistic computation of the particle’s spatial distribution. One way to quantify the turbulent dispersion of particles is to determine how the mean square dispersion of the particles，<x’2pi>，changes with time。Nevertheless，very few Lagrangian velocity autocorrelation function information are available in the published literature。 The measured raw data in the well-defined experiment of a planar，two-phase mixing-layer flow which was conducted by Wang and coworkers are used to determine the Lagrangian velocity autocorrelation functions for both the carrier and dispersed phases。The study reveals that the Lagrangian integral time scales along the streamwise (predominant) flow direction，τLi，of the carrier fluid in the two-phase case are largen than those in the single-phase case。Furthermore，the choice of Δτ is important in determination of experimental data of the Lagrangian velocity autocorrelation。The Lagrangian integral time scale for the dispersed phase is different from that for the carrier fluid，and dependent on the particle size。