While the WISE faculty will be open to suggestions on research topics, we wanted to list current research
thrusts which have been or are currently being pursued by past and current Texas Tech University Wind Science and Engineering students:
Establishing a Statistical Model Relating Ground-Based and Remotely-Sensed Building Damage in Windstorms:
Ground-based surveys of windstorm damage have been frequently performed in the past with the aid of aerial photographs in some cases.
Researchers have recently begun using remote-sensing data to assess damage following natural and man-made disasters, including digitized
satellite, aerial, and LIDAR imagery. This research is aimed at establishing the relationship between building damage states observed at
the ground, and those observed from space by leveraging prior work in the Enhanced Fujita (EF) rating scales for tornadoes and the Remote-
Sensing (RS) Damage Scale for hurricanes. Ground-based datasets include digital images acquired by VIEWS surveys for Hurricane Katrina in
2005 in Mississippi, and the “Super Tuesday” tornadoes in 2008 in Tennessee. Remote-sensing datasets include NOAA aerial photographs for
Hurricane Katrina, and QuickBird and WorldView I satellite imagery for the “Super Tuesday” tornadoes. Individual single-family homes will be
rated using the EF-scale for ground-based damage, and using the RS-scale for remotely-sensed damage. (T. Brown)
Hyperspectral Image Processing in A Hurricane Damage Study Hyperspectral remote sensing has shown great potential for
disaster analysis. In post-disaster urban damage assessment, residential areas and buildings must be accurately identified in the images before
and after the disaster. However, the traditional purely-spectral or purely-spatial solutions prove ineffective for residence detection
from low resolution hyperspectral images, such as Hyperion data. Thus, a joint solution of residential area classification, based on both
spectral signature and macrospcopic spatial texture, is proposed and developed. An improved accuracy of classification between residential and
natural areas is achieved on Hyperion satellite data taken over Lubbock, TX, and New Orleans, LA, respectively. (L.Cong)
Probabilistic Modeling of Metal Buildings and Loss Estimation: A methodology is being developed to predict the probabilistic
damage to the roof of a metal building in an event of a hurricane. The research presents a process of developing damage and economic loss
models for metal buildings based on the loss of roofing. The wind tunnel data generated by University of Western Ontario as a part of
NIST/TTU agreement program is used develop the models. An Artificial Neural Network model is used to predict the damage to similar buildings
where wind tunnel data is not available. (A. Dabral)
Creating a Reliability-Based Algorithm to Develop Structure-Specific Damage Scenarios:
A stochastic damage risk algorithm is being developed that will generate a structure specific damage scenario for
an extreme wind event. This work is an expansion of the TTU/GEMA Integrity program developed at Texas Tech University’s
Wind Science and Engineering Research Center in 2003. Currently, the TTU/GEMA Integrity program calculates resistance
values deterministically based on material types, member sizes and locations, component and cladding characteristics and
support and connection criterion all unique to the structure itself. The next iteration of this model will produce damage scenarios using reliability-based methods focusing on
variations in components and cladding when altering distribution types, means and standard deviations of random variables comprising
prescribed, material specific strength equations and the fundamental wind loading equation in ASCE 7 Chapter 6. The application of
a structure specific model has distinct advantages over widely used inventory approaches currently utilized by insurance and
reinsurance firms. The move to reliability methods using aggregated data other than deterministic values is the next paradigm shift
in structural analysis and design. Analogous methods are already prevalent in the seismic-structural community due to similarities
in the variation of the loading environment. (J. Dannemiller)
Short-Term Forecasting of Wind Energy: The goal of this work is to incorporate a wide range of meteorologically
relevant information into cutting edge prediction methods for wind energy forecasts. The time scales of interest are from less than
one hour up to several hours ahead. This work represents an amalgam of theories and concepts of boundary layer meteorology, system
predictability, evolutionary computing, wind engineering, and wind power systems. (P. Fowler)
Observations of Tropical Cyclone Low-level Wind Maxima: The development an implementation of Global Positioning System
dropwindsondes in 1997 has led to a wealth of new information from the hurricane boundary layer. Observations have revealed the presence
of significant wind speed maxima at altitudes below 500 m which represent a departure from code specified wind profiles. The presence of
low-level wind maxima could represent a threat to high-rise structures along the immediate coastline. This study attempts to characterize
the features as well as to identify their representative scales of motion, identify their presence at landfall, and to quantify their
impact. (I. Giammanco)
Probablistic Extreme Response Analysis of Large Wind Turbines to Natural Wind:
Completing an evaluation of the 5 MW wind turbine's aeroelastic respone and stability with FAST and TurbSim software to determine
how aerodynamic forces on blades affect the structural dynamics of the turbine system. The single and multi-variate Gaussian and
non-Gaussian wind flows with prescribed spectral and distribution characteristics will be simulated to analyze the sensitivity of the
various wind turbine component responses to the changing of Gaussian and non-Guassian wind parameters.(K. Gong)
Prognostic Independent Blade Pitch and Yaw Control Using Rotor Hub-Mounted LIDAR:
A Lidar is a laser anemometry device used in various scientific disciplines. In the wind Industry, the Lidar is applicable to detect
wind speed and direction. One of the current areas in wind energy research is to enhance the efficiency of the wind turbines as
well as mitigate the loads acting on the rotor unit. To serve this cause, a Lidar device which can be mounted on the rotor hub,
would be able to detect the wind speeds (200 – 400m) ahead of the rotor and this data can be fed to the control algorithm of
the blade pitch and rotor yaw control system. As independent blade pitch control is one of the recent advances in the rotor design,
its integration with a better wind speed detection device would probably enhance the efficiency of the machine. Moreover, as we know
that blades are prone to fatigue failures due to stochastic wind speed and vertical shear characteristics, the deployment of a
Lidar on the rotor hub would be an added advantage towards the load mitigation on the blades. Lidar is proposed to be used as the
data acquisition system in this research. The data obtained will be fed to the control system of the wind turbine, where a
predefined transfer function and algorithm would take the data as input state variables. Relevant output variables would be
transferred to the actuators mounted in blades pitching and rotor yawing gear mechanism. (A. Jain)
Analysis 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. 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. Thunderstorms have been hypothesized to exhibit varying flow characteristics, have different
vertical wind profiles than traditional boundary layer events, and dominate most extreme wind climates, making these events important
to consider for codification purposes. A new definition of pressure coefficient is proposed by constructing a time varying mean dynamic
pressure. Using this definition, pressure data can likely be transformed into a stationary time history and can be compared with
conventional pressure coefficients calculated at the WERFL site. Another 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 may significantly alter bluff body flow in a short period of time. (F. Lombardo)
Ingestion of Wakes from Upwind Turbines:
Whenever an upwind turbine wake is ingested by a downstream turbine rotor, the turbine operation cost and the cost of energy
increases since the downwind rotor is at least partially immersed in the low momentum wake. Also the downwind rotor intersects
with the complex vorticity field, thus reducing the fatigue life. Computational methods to investigate this situation are
being analyzed in order to propose a research approach and solve the problem. (N. Marathe)
Coastal Transition Zone: A collective investigation of 3D wind fields derived from SMART radar data, wind validation
from tower observations, and topography/land use data is being analyzed from Hurricane Frances in order to better understand the coastal
onshore internal boundary layer. (M. Martinez)
Pitch Control Modeling and Analysis for Optimized Wind Turbine Performance:
The blade pitch actuation and control system is a critical control component of modern wind turbines, enabling
efficient operation and reduced system loads to extend operational life. As the size and scale of these massive machines
increase, the functionality of the pitch system becomes increasingly important. In addition, the wind turbine industry
is moving towards individual blade pitch control systems in an effort to achieve further increases in system reliability,
durability and precision. Thus, the goal of research is to investigate and define an improved pitch control algorithm that
optimizes the tradeoffs among system loads, fatigue, and output power regulation. (R. Mathur)
Inhomogeneous, non-Gaussian Low-Level Jet Simulation: Implications for Wind Turbine Fatigue Loads: Currently wind turbine
design practice assumes that wind inflow turbulence can be simulated as a Gaussian process. Wind records from low-level jet events show that
the wind field is actually inhomogeneous, with some parts of the wind field covering the rotor grid well approximated by Gaussian statistics
and others best described with non-Gaussian statistics. Using data from the 200 m tower at Texas Tech University, a highly inhomogeneous low-level
jet inflow field is created matching observed statistics and used to excite a baseline 1.5 megawatt wind turbine using FAST.
(J. McNeill)
Turbulence characteristics of high wind events: The study incorporates the use of data collected during the
Synoptic Wind and Thunderstorm Hurricane field experiment of various high wind events (including thunderstorm outflows, hurricanes,
downward-mixing upper low pressure systems, and cold front passages). Relatively new nonstationary and nonlinear techniques will be utilized
to analyze each of the events, from which a formal comparison will be made between events and simulated data. (K.Orwig)
Firming Wind Energy with Solar Photovoltaics: Analysis of economic estimates of the ability of wind farm operators
to secure higher prices for power by reducing the uncertainty of production.
(M.C. Pattison)
Remote Sensing of Tropical Cyclone Development in West Africa: Many tropical cyclones that impact the United States
every year have their origins from African Easterly Waves (AEWs) passing over the Cape Verde Islands off the coast of West Africa.
The NASA African Monsoon Multidisciplinary Analyses field project in 2006 was carried out to gain a better understanding of hydrology
patterns in West Africa as well as to distinguish characteristics of AEWs that develop into tropical cyclones from those that do not.
This research involves using both traditional Doppler as well as newer polarimetric radars, various satellite platforms as well as
verification with in-situ sampling with research aircraft to investigate the microphysical and kinematic characteristics of organized
systems that initiate over the African continent and can eventually form tropical cyclones. This international field project has
involved collaboration with the National Center for Atmospheric Research, Howard University, Colorado State University, University
of Virginia, University of North Dakota, Cheikh Anta Diop University in Dakar, Senegal, and Meteo-France among others. (A. Reynolds)
TTUKa Dual Doppler Observations of Thunderstorm Outflow in VORTEX-2:
The 2010 campaign of the 2nd Verification of the Origin of Rotation in Tornadoes Experiment (VORTEX-2) marked the first occasion
that the two TTUKa mobile Doppler radars were deployed in tandem in a severe storm environment. Analysis of a long-term dual-Doppler
TTUKA dataset collected within a pre-tornadic supercell occurring near Dumas, TX, on 18 May, 2010, revealed the presence of multiple,
rapidly evolving internal rear-flank gust front boundaries. Dual-Doppler data of the Dumas supecell rear-flank downdraft from three
different elevation angles are currently being studied with a focus on the vertical structure and evolution of different rear-flank
downdraft "surges" and their potential applications to wind engineering. (P. Skinner)
Wind directionality effects: These studies aim to provide a probabilistic approach to wind predictions and assessments
considering spatial variations of the wind. The research will provide a better understanding for safe and reliable building designs
as also better performance of wind power resources. (R.Vega)
Wind Shear and Wind Power Systems: The impacts of speed and directional shear on both the power performance and
structural fatigue loading of modern megawatt-scale wind turbines. (K. Walter)
Remote Sensing of Wind Damage: Remote sensing from aerial and satellite platforms provides a method to significantly
increase the timeliness and extent of windstorm damage information. Research includes the qualitative and quantitative definition of
windstorm damage from a remote-sensing perspective and the automation of windstorm damage through correlation of remote-sensing damage
signatures with field observations. (A. Womble)
The Development of Force Coefficient Surface Fits from a Comparison of Full and Model Scale Signboards:
Previous research conducted by Texas Tech WISE has collected data for comparison between a full-scale sign prototype
(7.49m x 3.75m x 1.75m) and a 1:150 scale wind tunnel model (0.1524m x 0.0762m x 0.0254m). Comparison between pressure,
force and eccentricity coefficients were reported in "Field and Wind Tunnel Testing of Signs" report submitted to the
International Sign Association (ISA) and the Outdoor Advertising Association of America (OAAA). The current research is to
advance the understanding of wind engineering by developing curve and surface fits for the previously found data. The end goal
is to develop an equation for force coefficients that takes into account surface roughness, aspect ratio, clearance ratio,
and angle of attack. (S. Wayne)
Wind-Wave Interaction in the Nearshore Environment: With over 35 million people currently living in hurricane prone
coastal regions stretching from Texas to North Carolina, and the inevitable fact that this population will continue to increase, it is
pertinent that landfalling tropical systems are rigorously mitigated. Current research projects aim to advance our understanding of
nearshore air/sea momentum exchange via novel laboratory and observational studies. Since full scale measurements are exceptionally
arduous, the Boundary Layer Wind Tunnel at Texas Tech University (TTU) is used to study drag over a statistically valid nearshore wave
shape. This technique may prove to be a viable option to further our understanding of nearshore wind stress. Extremely rare
measurements of nearshore wind and waves were obtained during the passage of Hurricane Ike (2008) using TTU StickNet platforms and
University of Florida/Notre Dame wave/surge gauges, respectively. These data are used to determine drag coefficient behavior from
wind measurements in true marine exposure with knowledge of the local wave conditions. Outcomes are expected to improve the accuracy
of hurricane storm surge forecasts, and significantly affect coastal design standards for structures located in hurricane prone regions. (B. Zachry)
To access TTU's collection of theses and
dissertations from other academic disciplines, please click here.(Only those submitted after January 01, 2005, have been digitized.).
Texas Tech University, Wind Science and Engineering Research Center, 10th and Akron, Lubbock, TX 79409
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