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Full-Text Articles in Engineering
Using Blade Element Momentum Methods With Gradient-Based Design Optimization, Andrew Ning
Using Blade Element Momentum Methods With Gradient-Based Design Optimization, Andrew Ning
Faculty Publications
Blade element momentum methods are widely used for initial aerodynamic analysis of propellers and wind turbines. A wide variety of correction methods exist, but common to all variations, a pair of residuals are converged to ensure compatibility between the two theories. This paper shows how to rearrange the sequence of calculations reducing to a single residual. This yields the significant advantage that convergence can be guaranteed and to machine precision. Both of these considerations are particularly important for gradient- based optimization where a wide variety of atypical inputs may be explored, and where tight convergence is necessary for accurate derivative …
Development And Validation Of A New Blade Element Momentum Skewed-Wake Model Within Aerodyn, Andrew Ning, Greg Hayman, Rick Damiani, Jason Jonkman
Development And Validation Of A New Blade Element Momentum Skewed-Wake Model Within Aerodyn, Andrew Ning, Greg Hayman, Rick Damiani, Jason Jonkman
Faculty Publications
Blade element momentum methods, though conceptually simple, are highly useful for analyzing wind turbines aerodynamics and are widely used in many design and analysis applications. A new version of AeroDyn is being developed to take advantage of new robust solution methodologies, conform to a new modularization framework for National Renewable Energy Laboratory’s FAST, utilize advanced skewed-wake analysis methods, fix limitations with previous implementations, and to enable modeling of highly flexible and nonstraight blades. This paper reviews blade element momentum theory and several of the options available for analyzing skewed inflow. AeroDyn implementation details are described for the benefit of users …
A Simple Solution Method For The Blade Element Momentum Equations With Guaranteed Convergence, Andrew Ning
A Simple Solution Method For The Blade Element Momentum Equations With Guaranteed Convergence, Andrew Ning
Faculty Publications
The blade element momentum equations, though conceptually simple, can be challenging to solve reliably and efficiently with high precision. These requirements are particularly important for efficient rotor blade optimization that utilizes gradient-based algorithms. Many solution approaches exist for numerically converging the axial and tangential induction factors. These methods all generally suffer from a lack of robustness in some regions of the rotor blade design space, or require significantly increased complexity to promote convergence. The approach described here allows for the blade element momentum equations to be parameterized by one variable: the local inflow angle. This reduction is mathematically equivalent, but …