Analyzing the Effects of Topography on High-Altitude Balloon Descent

Abstract

This project was developed to improve upon an experimentally-based descent prediction program for high-altitude balloon payloads at the Montana Space Grant Consortium’s Balloon Outreach, Research, Exploration And Landscape Imaging System (BOREALIS) program. The high-altitude balloon payloads were launched from flat tarmacs but generally landed in or near mountainous terrain. Terrain has a significant effect on air flow, and thus this project was developed in order to improve the accuracy of the predicted landing latitude and longitude. The project was broken into two parts. The first part was simplifying and solving the Navier-Stokes equations to predict an external wind field incorporating the effects of topography. Since the payload would be entering a steady velocity field, we deduced, with the support of external research, that we could simplify the Reynolds Averaged Navier-Stokes equations. Our final simplified equations were solved on a 100 × 100 grid. The second portion was tracking the position of the payload through the grid using interpolation techniques and Newtonian physics.