This week, we’re highlighting two commands that allow for greater flexibility in defining target times during your HydroGeoSphere simulations: target times and generate target times.

This post describes how to use the scaling factor command to adjust time series inputs directly within a boundary condition block in your prefix.grok file. Conceptually, this allows users to scale boundary condition inputs— like fluxes or concentrations— on the fly, without needing to modify large or externally sourced input files. While a straightforward use is unit conversion, we find this command especially useful for quick input calibration during model tuning, allowing users to easily explore how different scaling choices influence model results.

This post explains how to interpret the runtime output generated by HGS during each timestep while computing the flow solution. The output is useful for tracking the convergence of the simulation and diagnosing potential performance issues. Conceptually, the runtime output helps monitor the progress of the simulation and iteration steps, providing critical information on how the solver is performing. By understanding the output, users can adjust their simulation parameters and ensure accurate results. We find this detailed output particularly valuable when troubleshooting and improving model performance.

This post highlights a key tool for evaluating solute transport and density-dependent flow models: the output peclet number command. When building these models, a common approach is to first establish a steady-state flow solution, then validate transport using flow outputs as initial conditions, and finally introduce density dependence if needed.