MRI: Development of a Versatile, Self-Configuring Turbulent Flow Condition System for a Shared-Use Hybrid Low-Speed Wind Tunnel

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MRI: Develop Inastrumentation to Advance Fundamental Research on Simulating Complex Wind Flow Near the Earth's SurfaceThe boundary layer wind tunnel is an essential research tool for creating dynamic wind flow that replicates the natural behavior of wind near the Earth?s surface. This wind flow is applied to models of buildings and other structures to determine their expected performance and to design them to survive extreme wind events. The accurate replication of natural wind in a laboratory is not trivial. The methods and equipment vary depending upon the wind condition (tornadoes, hurricanes, thunderstorms, etc.), and the geographic location of the object being studied (near the coast, in a suburban community, etc.). Current wind tunnel facilities are limited in this regard, each capable of addressing a small subset of wind phenomena. This award supports the development of an instrument that vastly expands the capability of a single facility to study a wide range of wind conditions observed in nature and assess how they affect the built and natural environments. This capability will accelerate the rate of discovery and open pathways to solving problems in the development of resilient infrastructure. Other applications include the study of pollutant dispersion, siting of wind energy resources, biomechanics, human perception of hazards, and micro aerial vehicle development. The project includes participants from five continents. Thus the development of this instrument will strengthen US competitiveness by enabling a breakthrough in boundary layer wind tunnel technology, while enhancing international collaboration on wind hazard issues that impact the entire populated world.The objective is to develop an instrument capable of simulating nonstationary, non-neutral or transitioning surface flows. Examples include offshore hurricane winds flowing into a terrestrial environment, non-stationary gust fronts in thunderstorms, transient coherent structures induced by the shearing motion aloft and wind-driven rain. The instrument will command static and dynamic control devices that automatically reconfigure to achieve user-specified similarity requirements such as non-monotonic profiles, spatially variable power spectra and integral length scales, transient gusts, and rain entrainment in the flow field. These control devices must work in series (one stage conditions the next) to achieve the intended function of the instrument. The instrument includes components adapted from existing proof-of-concept studies and new technology to be developed. The framework on which the instrument is to be developed is a conventional boundary layer wind tunnel design, as a goal is to create a tool suitable for implementation in facilities worldwide.