Analysis and interpretation of non-stationary wind flow on a bluff body

Non-stationary wind and pressure data has long been problematic to the wind engineering community due to its inherent transient characteristics, making it impractical to use traditional correlation and spectral analysis techniques. Due to these constraints, appropriate and meaningful analysis has been rather limited. Inconveniently, some of the more interesting and important wind data from an engineering perspective usually exhibit non-stationary characteristics (e.g., hurricanes, thunderstorms, tornadoes). A number of non-stationary wind and pressure records exist at the Texas Tech Wind Engineering Research Field Laboratory (WERFL) building, mainly due to thunderstorms which frequent the area throughout the spring and summer months. An important aspect of the research is to analyze the characteristics of wind flow and pressure distribution around the WERFL building in strongly non-stationary, or "ramp-up" events where strong changes in wind speed or wind direction or other flow mechanisms such as "ring vortices" from microbursts may significantly alter bluff body flow in a short period of time. Wavelet analysis again has many advantages for this type of local (evolving) information as it can be used for analyzing and quantifying continuous information in the time and frequency domain. Indirect bluff body effects such as vertical angle of attack and vertical wind speed profile will also be identified during thunderstorm/non-stationary events. Angle of attack showed no significant differences while some thunderstorm profiles exhibited impinging jet profile in a "gust" sense.