A Computer Model for the Evaluation of Helicopter Fire Control Systems

A potential-flow panel method was modified to calculate the effects of a rotor wake on the time-averaged surface pressure and velocity distributions on a helicopter fuselage. The rotor-induced velocities are calculated by using a vortex-tube wake model. The calculated pressure distributions are found to compare well with experimental data obtained from tests of a wind-tunnel model.

Development and validation of a combined rotor fuselage induced flow field computational method

The aerodynamics of a wind turbine is governed by the flow
around the rotor, where the prediction of air loads on rotor
blades in different operational conditions and its relation to rotor structural dynamics is crucial for design purposes. One of the most important challenges in wind turbine aerodynamics is therefore to accurately predict the forces on the blade, where the blade and wake are modeled by different approaches such as the Blade Element Momentum (BEM) theory, the vortex method and Computational Fluid Dynamics (CFD).
A free vortex wake method, based on the potential, inviscid
and irrotational flow, is developed to study the aerodynamic
loads. The results are compared with the BEM method,
the GENUVP code and CFD.

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Development of Free Vortex Wake Method for Aerodynamic Loads on Rotor Blades

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Inviscid flow field induced by a rotor in ground effect

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982.

Computational methods for non-planar vortex wake flow fields with applications to conventional and rotating wings

: The report discusses the development of a propeller wake model and computational procedure aimed at the determination of the spatial distribution of wake vorticity and the associated induced velocity distribution. Numerical calculations were made for a number of vortex-ring configurations corresponding to a hovering rotor at onehalf, one and two ring radii above the ground, as well as out-of-ground effect. Both unsteady and time-averaged velocities were computed at various points in the wake for several cases. A model is proposed for the wake flow of a rotor in steady forward flight. Instead of the vortexring representation, the tip vortices are represented by continuous finite-core vortices. For purposes of numerical calculation, the continuous vortex is approximated by short straight-line segments. This model will enable the calculation of the time-dependent wake-vortex configuration, within the limitations of practicable computing running time, in which the various vortex elements move under mutual influence according to the laws of vortex dynamics. (Author)

W. Gordon Brady

Papers

Representation of propeller wakes by systems of finite core vortices.