Wind tunnels were invented in the early 1900s to test aircraft, which either fly in relatively quiet atmospheric conditions or are so large and heavy that they are largely unaffected by turbulence. These wind tunnels were thus designed to have low turbulence and uniform flow.

However, laminar, low turbulence, steady, and flat-profile winds are not representative of atmospheric conditions near the ground. Such wind tunnels are thus inadequate for the study of low-altitude phenomena (Atmospheric Boundary Layer flows) and ground-level, human-scale technologies (such as drones, wind turbines, sailing, etc.).

For instance, when aeronautical wind tunnels started being used to test civil engineering models (buildings, bridges, etc.), they needed to be modified with added perturbations, either passive (grids, roughness elements) or active (vibrating 2D blades, active grids) to reproduce the characteristics of atmospheric flows.

For drones, manufacturers have no choice other than performing tests in the outdoors. However, this testing methodology suffers from many drawbacks, including poor accuracy, lack of reproducibility, dependence on day-by-day weather forecast, unknown and non-controllable flow conditions, short test times, large distance between drone and tester.

In order to resolve the issues associated with traditional wind tunnels or outdoor testing protocols, we have developed a real wind and weather simulator based on a multi-fan technology (windshaper). This tool enables testing in various and controllable atmospheric conditions, including arbitrary wind speed and direction, as well as turbulence, hail, rain, snow, and sandstorms. The novel wind facility allows free-flight (for drones), is completely modular, can be assembled in any desired geometry, and can be made as large as desired while maintaining a small footprint. It is capable of generating gusts (temporally varying winds) and arbitrary wind profiles (shear flows) in any direction.

The large number of degrees of freedom associated with multiple fans in combination with the intricate (and yet unknown) nature of environmental flows at human scale, will nurture a variety of research avenues for years to come. Windshapers will be a playground for understanding and mastering the interaction of natural and human-made structures with complex aerodynamic flows.

Bio:

Dr Noca received his PhD in Aeronautics from the California Institute of Technology (Caltech) in Pasadena. He then worked as a research engineer at NASA Jet Propulsion Laboratory (JPL) for almost ten years, while holding a lecturer position at Caltech in Aeronautics and Bioengineering. He then joined the University of Applied Sciences in Geneva, Switzerland, as an Associate Professor of Aerodynamics. He is currently a Research Associate and Lecturer at EPFL (Ecole Polytechnique Fédérale de Lausanne, Switzerland). Dr Noca has been awarded several patents and has authored publications that have gained recognition in the field of unsteady aerodynamics. He is co-founder of a company, WindShape, which manufactures real wind & weather test facilities (windshapers) for universities and research institutions worldwide. WindShape will soon open and manage in Tulsa, OK, a large-scale center for uncrewed aircraft testing and certification.