CFD Analysis of Fan Wall Downstream Flow for UAS Testing

The push towards greater autonomy of aerial vehicles requires an extensive knowledge of the environment and forces that will act on these vehicles during their flights. However, creating a somewhat analytical or perfect control system is an extremely difficult physics problem in the face of the nearly unpredictable nature of turbulence. Thus, experimentation is critical for incremental improvement. To achieve a repeatable experimentation process for UAS testing, a "fan wall" consisting of numerous individual fans, called the Windshaper, will be used to build a faux wind tunnel testing system that allows for various different profiles and disturbances to be generated. To effectively use this system to test UASs, a CFD model for the inside of the testing facility must be generated. This model can help prescribe the bounds of a valid test space, by portraying the distance before the downstream breakdown of the flow occurs for a given profile. Furthermore, the model will be critical in assessing the safety of containing a wind-generating device in an open-air test section. The sensitivity of the simulation to its turbulence model and meshing fidelity must also be verified. Ultimately, the accuracy of the model will then be validated with actual pressure measurements.