Applying Mesh Adaption to Modeling Supercritical Flow

A numerical model study of the Hoosic River in North Adams, MA was conducted to determine flow conditions at up-dated flood discharges. The study reach of the Hoosic River is a man-made concrete lined steep channel. The flows are conveyed as supercritical. The design of this high-velocity channel was evaluated and refined in a physical madel study completed in the 1950's. The current study is a validation of the Adaptive Hydraulics (ADH) shallow-water code to capture the flow features within this complicated channel. The ADH code was used to simulate the supercritical flow and the results are compared to the physical model data. The project is a good test of the model's ability to simulate the complicated flow throughout the study reach. The reach contains 23 curves with compound spirals and invert banking, a confluence of two supercritical channels, and a twin stilling basin to contain hydraulic jumps prior to introducing the flow to a soft-bottom channel. The longest tangent between compound curves is less than 5 times the channel width. Most curves are adjoined in that the spiral-to-tangent (ST) ending one curve and the tangent-to-spiral (TS) beginning the next curve share the same station. The numerical model results are compared with previously published physical model data. Issues such as mesh adaption and resolution are investigated. Also the ability of the shallow-water equations to simulate the additive effects of adjoining curves is tested.