Three-Dimensional Velocity Field Measurements in Rugged Terrain Using Magnetic Resonance Velocimetry

Magnetic resonance imaging techniques were used to collect three-dimensional velocity data measurements of scaled models of a canyon in New Mexico to compare to simulations where a gas was released inside the canyon. The first canyon model covers an area of 1850m × 1030m with a scale of 1:5250 while the second model covers an area of 290m × 160m with a scale of 1:825. A fully turbulent flow with a Reynolds number of 36,000 using the channel hydraulic diameter passes through the canyon geometry for both models. With Magnetic Resonance Velocimetry (MRV), more than 13 million data points were measured to represent flow velocity. The MRV experiment with the 1:5250 scale model helped to identify key terrain features to be included in the next set of measurements of a higher resolution model. MRV not only served as a method of analysis but also as a method for design. The analysis of the data resulted in a new design of a 1:825 scale, which had a higher resolution of the terrain surrounding the gas release point. The preliminary scans from the 1:825 scale model showed a much more dynamic flow around the release point than observed in the 1:5250 scale model. Counter-rotating vortices and circulation can be observed in the 1:825 scale model. This data set will be used to compare to Sandia National Laboratories’ simulations of turbulent flows in a complex terrain.