Wind engineering research field laboratory site characterization

Wind flow parameters obtained from the field data are simulated in the wind tunnel for studying wind effects on structures. The wind flow parameters include power law exponent (a), surface roughness (zo), shear velocity (u*), and longitudinal, lateral, and the vertical turbulence intensity (lu, Iv, and I^). The results of the wind tunnel study depend on the reliability of wind flow parameters measured in the field and the simulation technique. The objective of this work is to investigate the characteristics of the wind flow parameters at the Wind Engineering Research Field Laboratory (WERFL) in light of the factors which may affect the parameters. The factors investigated include: mean wind direction, mean wind speed, stationarity, atmospheric conditions, time of day a record was collected, and time of year a record was collected.

The National Science Foundation has sponsored a Colorado State University/Texas Tech University Cooperative Wind Engineering Program at the Texas Tech University Wind Engineering Research Field Laboratory (WERFL) to study wind effects on low-rise buildings. Wind and meteorological data are collected on a 160 ft high meteorological tower. The data collected for this project includes wind speed and wind direction at four levels on the meteorological tower. Wind speed and direction were used to assess the wind parameters and perform the characterization of the terrain.

The scope of this project is limited to data collected between April of 1991 and June of 1992 (Mode 15 data). A total of 465, 15-minute records were collected of which 454 records were found to be acceptable for analysis.

The analysis of the data included plotting of the parameters versus the factors, estimation of probability density functions for the parameters, and nonparametric statistical testing. Interpretation of the analyses and observations from the data analysis revealed wind from all directions does not yield the same mean and variance of the parameters. The wind parameters show that stationarity is not an important factor for the site characterization. Shear velocity is a function of wind speed.