A 3-COMPONENT LDV SYSTEM FOR MEASUREMENTS OF HIGHER STATISTICAL MOMENTS IN TURBULENT-DIFFUSION FLAMES

A three-component LD V system was built with the following features: 1 . Three colors, 2. Forward scattering, 3. Direction determination, 4. Avalanche photodiodes, 5. Transient recorder, 6. Fast Fourier transfor m. With this equipment measurements in a free air jet and a turbulent methane nitrogen diffusion flame were made. The following quantities w ere determined on the axis and on some levels: velocities u(i), spread ing rate r(0.5.uc)/d, centerline velocity-decay u0/u(c), Reynolds-stre ss tensor u'(i)u'(j) and all third order moments u'(i)u'(j)u'(k). Thes e quantities were normalized and compared with literature data and wit h Reynolds-stress model calculations. One of the main objectives of th ese measurements was the supply of exit velocity profiles because the predictions below the similarity region depend crucially on the bounda ry conditions. In this paper details of the equipment and of the data processing are explained and new results are shown.