Aubryn Cooperman

• PhD
• Analyst at National Renewable Energy Laboratory

Floating offshore wind technology allows wind energy systems to be deployed in water depths that are inaccessible with conventional fixed-bottom technology, of which more than 60 GW is already installed. Several floating offshore wind energy pilot projects have demonstrated reliable operation of the technology in water depths between 200 m and 300...

NREL developed recommendations for a representative project design envelope (RPDE) for floating offshore wind energy projects in the California lease areas, considering industry feedback from offshore wind farm developers. The RPDE provides estimates of minimum and maximum values for project design parameters that are relevant for assessing environ...

Operations and maintenance (O&M) of floating offshore wind farms (FOWFs) poses various challenges in terms of greater distances from the shore, harsher weather conditions, and restricted mobility options. Robotic systems have the potential to automate some parts of the O&M leading to continuous feature‐rich data acquisition, operational efficiency,...

Lubrication is a key aspect of maintaining a wind turbine in operational condition. In this study, we quantify the potential for increasing energy production and reducing maintenance costs across the current and future U.S. fleet of wind turbines as a result of improvements in lubrication performance. The modeled improvements reduce the median leve...

The growing number of end-of-life (EOL) wind blades could further strain US landfills or be a valuable composite materials source, depending on stakeholders’ behaviors. Technical solutions based on circular economy (CE) principles have been proposed but are not guaranteed to solve the issue of EOL management. Transitioning to CE implies changing ho...

Turbine and plant upsizing are major trends in offshore wind deployment, although the quantitative impact on project costs has not been well-characterized. The uncertain value of continued wind turbine and project growth limits the ability of the supply chain to prepare for future technology trends, leading to challenges in the realization of large...

Wind energy has experienced enormous growth in the past few decades; as a result, there are thousands of wind turbines around the world that will reach the end of their design lifetimes in the coming years. Much of the material in those turbines can be recycled using conventional processes, but the composite material that is the main component of t...

Various characteristics of small surface-normal jets (microjets) located on a flap’s pressure-side near the trailing edge are investigated as an active aerodynamic load control technology for multi-element high-lift systems. Two-dimensional computational studies are carried out to investigate the sensitivity of microjet aerodynamic effectiveness to...

The costs of wind power have declined to levels on par with or below those of conventional sources in many parts of the world. Wind power has become one of the fastest‐growing sources of new electricity generation. We take stock of wind power cost evolution over the past 20 years, review methodologies commonly used for cost assessment, discuss the...

This study investigates the performance of microjets for load reduction on the NREL-5 MW wind turbine and identifies optimal system parameters. Microjets provide blowing normal to the blade surface and can rapidly increase or decrease lift on a blade section, enabling a wind turbine to respond to local, short-term changes in wind condition. As wind...

This study demonstrates improvements in ensemble wind forecasts at hub height due to bias correction strategies and their impact on wind energy forecasts at the Alta II wind farm in southern California. The ensemble consists of twenty members that differ in physics schemes used. Ensemble wind forecasts are produced for three months. Hub-height soda...

Experimental and computational examinations of the effect of splitter plate length on the aerodynamic performance and vortex shedding behavior of a blunt trailing-edge airfoil are presented along with an evaluation of spanwise shedding coherence. The FB-3500-1750 airfoil, which has a maximum thickness of 35% chord and trailingedge thickness of 17.5...

This study presents an innovative design of a microtab system for aerodynamic load control on horizontal-axis wind-turbine rotors. Microtabs are small devices located near the trailing edge of the rotor blades and enable a rapid increase or decrease of the lift force through deployment of the tabs on the pressure or suction side of the airfoil, res...

Structural load monitoring of wind turbines is becoming increasingly important due increasing turbine size and offshore deployment. Rotor blades are key components that can be monitored by continuously measuring their deflection and thereby determining strain and loads on the blades. In this paper, a method is investigated for monitoring blade defo...

A closed-loop control system has been developed for microtabs and demonstrated in the University of California, Davis, Aeronautical Wind Tunnel. Input to the system comes from two dynamic pressure transducers located at 15% chord on the upper and lower surfaces of the airfoil. Microtabs with a height of1%chord are located at 95%chord on the lower s...

Two active aerodynamic load control (AALC) devices coupled with a control algorithm are shown to decrease the change in lift force experienced by an airfoil during a change in freestream velocity. Microtabs are small (1% chord) surfaces deployed perpendicular to an airfoil, while microjets are pneumatic jets with flow perpendicular to the surface o...

Structural health monitoring is becoming more valuable for wind energy producers as wind farms become larger and more remote. Increasing numbers of wind turbines are being installed offshore in order to take advantage of the higher wind speeds and more consistent wind resource available over the water. High winds and waves make access to offshore w...

This review article examines the range of sensors that have been proposed for monitoring wind turbine blade loads for the purpose of active load control over the past decade. Wind turbine active load control requires sensors that are able to detect loads as they occur, in order to enable a prompt actuation of control devices. Loads may be detected...

The dynamic response of an airfoil to microtab deployment has been studied in the University of California, Davis Aeronautical Wind Tunnel. Static tests were conducted at a Reynolds number of 1.0 × 106, whereas dynamic testing examined deploying microtabs under steady conditions and during simulated wind gusts. Experimental results are compared wit...

A fast, efficient way to control loads on utility scale wind turbines is important for the growth of the wind industry. Microtabs and microjets are two Active Aerodynamic Load Control devices, which address this need. Both act perpendicular to the surface of the airfoil, and these actively controlled devices are used to mitigate changes in aerodyna...

Flow around an S819 airfoil, which has been modified to have microjets near the trailing edge on both the pressure and suction surfaces, has been studied in both a wind tunnel and using the two-dimensional Reynolds-averaged Navier-Stokes solver OVERFLOW-2. Microjets are small jets of air blowing normal to the airfoil surface that can affect its aer...

Small, actively controlled tabs that deploy normal to an airfoil's surface (microtabs) and actively controlled jets that blow normal to the surface (microjets) have been proposed as potential mechanisms to provide aerodynamic load control on wind turbine blades. This paper describes the results of wind tunnel tests of each device, installed in the...

This study aims to provide experimental and computation data to fully characterize the dynamic effects of deploying microtabs for active load control on wind turbine blades. A wind turbine airfoil model with linearly actuated microtabs has been tested in the UC Davis Aeronautical Wind Tunnel. Initial tests were conducted under static conditions at...

This paper addresses the primary concerns regarding the aerodynamic performance characteristics of thick airfoils with blunt trailing edges (or so-called flatback airfoils) and the utilization of these section shapes in the design of rotor blades for utility-scale wind turbines. Results from wind tunnel and computational fluid dynamic studies demon...

An experimental and computational examination of the aerodynamic performance of a blunt trailing edge airfoil is presented. The UCD-38-095 airfoil is one of a family of thick airfoils designed using genetic and gradient-based optimization. Its maximum thickness is 38% of the airfoil chord, with a trailing edge thickness of 9.5%. In the present stud...