Effects of Concentration of Partial Seeding and Data Sample Size in Lda Measurements

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Yu Han, Xin Zhang, Shu-Qing Yang, Nadeesha Dharmasiri, Woo Taek Hong

Tuesday 30 june 2015

12:45 - 12:48h at Africa (level 0)

Themes: (T) Water engineering, (ST) Experimental facilities and instrumentation

Parallel session: Poster pitches: 5F. Engineering - Instrument

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A Laser Doppler Anemometer was used to measure the mean flow and turbulence in fluid experiments. Generally, the experiments will chose a sufficiently large data size to produce measurements free of statistical error, even with high turbulence intensity. However, there is no relative experimental validation to determine the reasonable data size for LDA system. This paper first proposes the reasonable data size to ensure a mean velocity calculation free of bias. Moreover, the effects of particle seeding concentration on the measurements of velocity were also considered. Throughout the experimental process the particle velocities were measured using a Dantec 2-D LDA system. To describe the effects of data size and particle seeding concentration, this paper will also address the reasonable data size and range of concentration in the design of water flow prior to any experimental application.