Investigation of Two-Dimensional Flow Measurements Using the Laser Doppler Technique

摘要

Specification of flow parameters in a moving fluid usually requires knowledge of velocity components in more than one dimension. Using the laser Doppler technique, velocity components may be measured with a great number of geometries. This study investigated combinations of geometries useful for constructing a two-dimensional velocimeter. Three systems underwent extensive study, two incident beam forward scatter, single incident beam forward scatter, and single incident beam forward and backward scatter. System parameters investigated experimentally and theoretically included cross-talk between beam polarization effects, relative scattering intensities, and measurement point constraints. Turbulent flow in a 4-inch-diameter pipe was used to demonstrate the measurement technique utilizing the single beam forward scatter system. Coordinate transformations between velocimeter coordinates and flow system coordinates were derived. (Author)