![]() ![]() These models span three orders of magnitude in computational time and cost for the study of HAWT aerodynamic performance and wake interaction. This methodology is applied to a canonical rotor and compared against experimental data. The Actuator Disk Model underestimates the velocity deficit in the far wake, but can be corrected to perform simulations of large wind farms. The Blade Element Model does not reproduce the near wake region but successfully predicts the velocity deficit in the axisymmetric far wake, and the power and torque coefficients. The Rotating Reference Frame model is prescribed for detailed flow field studies, specifically at the root and blade tip. Three models are systematically compared to determine their adequacy to capture performance and wake dynamics, and the trade-offs between accuracy and computational cost. Finally, the third case simulates the rotation of the nacelles during transition from the forward flight to the landing configuration of the V-22 Osprey using Fluent's dynamic mesh capabilities.Ī hierarchy of computational methods for Horizontal Axis Wind Turbine (HAWT) flow field is proposed, focusing on rotor models for Reynolds-Averaged Navier-Stokes simulations. The second case, the Apache AH-64 helicopter, investigates the interaction effects between the main and tail rotor. Pressure distributions on the airframe are compared with experimental data and good agreement is found. ![]() ![]() As validation example, a well-studied single rotor airframe interaction case in forward flight is discussed. Trimming is performed in an automatic and robust fashion using an iterative method to account for the non-linear relation between blade pitch and rotor performance. Accurate aerodynamic predictions are possible only if the rotors operate at desired thrust and zero moment about the hub. The non-linear, aerodynamic interaction between the rotor wakes with each other and with other structural components is solved by coupling the VBM with the governing flow field equations computed by Fluent's Navier-Stokes solvers. The model allows for an unstructured mesh in the rotor disks yielding easy meshing of multiple rotor geometries in close proximity and convenient local mesh clustering. Thus the effects of the blades are accounted for without them being present in the computational mesh, giving the model its name "Virtual Blade Model" or VBM. This technique models the rotors implicitly through source terms in the momentum equations. 1 and Yang et al.2 has been implemented into the general purpose solver Fluent. A method for analyzing the mutual aerodynamic interaction between multiple rotors and airframes in the spirit of Zori et al. ![]()
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