Three-dimensional velocity and concentration measurements and simulations of a scaled Jack Rabbit II mock urban array

Abstract

Abstract Magnetic resonance (MR) techniques provide non-invasive, three-dimensional measurements of velocity and concentration fields. Applying MR techniques to measure flows of contaminants through urban arrays provides a wealth of information that is difficult to obtain with large-scale field tests. In this project, a 1:188 scaled model of the phase 1 Jack Rabbit II field test was replicated and studied using a water tunnel with properties chosen to mimic field conditions. Three-dimensional, time-averaged flow data was measured using magnetic resonance velocimetry (MRV) and magnetic resonance concentration (MRC) techniques. The scaled flow was also modeled with large-eddy simulations (LES) to provide a dataset for comparison with the MR based measurements. Despite a complex, three-dimensional flow field, both velocity and concentration show good agreement between the experimental measurements and simulation data. Measurement uncertainty was estimated to be ± 5 % of each of the measured velocity components at each location for MRV and ± 4 % of the measured concentration at each location for MRC.