A vertical shock tube is used for experiments on the Richtmyer-Meshkov instability with a random, three-dimensional initial perturbation. A membrane-less interface is formed by opposed gas flows in which the light and heavy gases enter the shock tube from the top and from the bottom of the driven section. An air/SF6 gas combination is used and an M = 1.2 incident shock wave impulsively accelerates the interface. Oscillating two loudspeakers mounted in the shock tube wall creates an initial perturbation in the form of small, random, three-dimensional surface waves on the interface. Planar Mie scattering is used to visualize the flow using a laser sheet to illuminate smoke particles seeded in the air. Image sequences are captured using two high-speed video cameras. New experiments are presented in which the full three-dimensional initial perturbation is recorded immediately prior to shock interaction. A galvanometer system redirects the laser sheet to 29 locations with one image captured per location, producing a set of images through the test section volume. The resulting volumetric image is then used as the initial perturbation in numerical simulations. Comparisons are made between experimental measurements and those obtained from the simulations.
