Three-Dimensional Space-Time Structure of Turbulent Jets

Three-dimensional spatio-temporal concentration fields are measured in the far field of a liquid-phase axisymmetric turbulent jet. The LIF imaging experiments, which capture the entire local extent of the jet in a plane coincident with the jet axis, are spatially resolved to the diffusion length scale and temporally resolved with respect to the out-of-plane transport time τ_z = λ_\cal D / w'. The three-dimensional space-time structure of the turbulent mixing flow is visualized by computing isoconcentration surfaces. Image correlation velocimetry (ICV), which can infer velocity fields from a sequence of images of advected scalars, is applied to the LIF data to compute the estimated three-dimensional isosurface.