Actuator Line and Immersed Boundary Methods for Rotorcraft CFD

As part of a US-France Project Agreement, the US Army and ONERA are investigating mid-fidelity computational approaches for rotorcraft aerodynamics. The approaches from both groups use immersed boundaries in the place of boundary-layer-resolved meshes and actuator lines in the place of rotor blades. Results are compared between the US Army and ONERA to assess strengths and limitations of the mid-fidelity algorithms. An isolated rotor case is first used to validate and compare actuator line wake structure against a high-fidelity result. Second, a static coaxial hub is used to compare immersed boundary algorithms. In the final application, immersed boundary methods and actuator lines are used together for the Dauphin 365N configuration in forward flight.