On August 2, 1985, Delta Air Lines Flight 191 crashed at Dallas/Fort Worth Airport after flying through an extremely violent descending microburst. This meteorological phenomenon, characterized by air currents that plunge vertically and expand radially upon hitting the ground, generated a sudden change in wind direction and intensity that the crew could not counteract. The accident, which claimed 137 lives, marked a turning point in the understanding of microbursts and in the development of prediction and simulation technologies.
Reconstruction of the disaster using ANSYS Fluent and WRF đŠī¸
To digitally recreate the accident, engineers turn to multiphysics modeling combining the Weather Research and Forecasting Model (WRF) with ANSYS Fluent. WRF provides the large-scale atmospheric conditions that originated the storm, while Fluent breaks down the microburst into a high-resolution domain, solving the Navier-Stokes equations to capture vertical wind shear and the typical ring vortices of a downburst. The simulation reveals how the aircraft, at low altitude, experienced an abrupt loss of lift and a 50-knot tailwind gust, followed by a downdraft exceeding 1,000 feet per minute. This detailed analysis allows visualization of the fluid-structure interaction between the airflow and the fuselage.
3D visualization and lessons for airport safety âī¸
Houdini comes into play to transform CFD data into striking volumetric visualizations, showing streamlines colored by velocity and pressure gradients around the aircraft. These representations not only help understand the accident but also guide the design of new protocols: from installing TDWR (Terminal Doppler Weather Radar) systems to improving early warning algorithms. 3D simulation demonstrates that predicting a microburst is not enough; it is vital to model its exact interaction with each aircraft to save lives.
Could a modern CFD simulation of the Delta Flight 191 microburst reveal shear patterns undetected by the atmospheric models of 1985, and if so, how would this change current microburst warning protocols at airports?
(PS: Simulating disasters is fun until the computer crashes and you are the disaster.)