Recent developments in actuator methods to model lifting surfaces and their applications to wind turbines


Several actuator methods to model lifting surfaces (fixed wings as well as rotors) exist today. These methods vary in fidelity, starting from actuator-disk method being the lowest fidelity, followed by actuator-line method, and then by actuator-surface method. Actuator-line method (ALM) has recently found great importance in modeling wind turbines in a stand-alone mode as well as in wind farm. The medium-level fidelity and the proportional computational cost makes modeling of the flow-field in a wind farm using ALM affordable. However, in order to predict the blade loads, power produced, fatigue, the strength of the tip vortices, their break down, turbine-turbine interaction, etc. accurately, the rotors must be modeled as accurately as possible. The work done by the speaker, on the accuracy assessment of state-of-the art ALM and proposal of a modified ALM, has helped enhance the state-of-the-art in rotor modeling. This modified ALM (ALM*) was then applied to a turbine-turbine interaction problem where wake-wake and wake-atmospheric turbulence interaction were studied. The turbulence statistics and unsteadiness of blade loads were studied in detail. Having gained insight into the turbine-turbine interaction problem, ALM* was used to study the flow-field in a mini wind farm. An attempt was made to understand the wake recovery and meandering pattern in a wind farm using a unique wake-plane integration technique. An Actuator Curve Embedding (ACE) method was developed to model a general-shaped blade/curve. This new method takes the state-of-the-art of modeling lifting surfaces a step further and addresses some of the limitations of ALM.

Aug 15, 2017 10:00 AM — 11:00 AM
ATOC Conference Room, SEEC N224
Engineering Center, University of Colorado at Boulder, Boulder, CO 80309

Envision Energy