Abstract
In this paper, a new technique for simultaneous measurement of the density and velocity fields is proposed. In the experiments, the regions with a density distribution are inserted between the camera and liquid crystal display, on which a picture of the random pattern are projected. The random pattern displacement was tracked before the density distribution changed. The gradient of the logarithmic function of the refractive index in the area was measured, and the density distributions are numerically reconstructed. Using PIV with above method, both density and velocity distributions of the gravity current were measured simultaneously, and they are in close agreement with conventional measurements.
