Real-time Flow Field Aerodynamics Two-way Coupled to Rotorcraft Flight Dynamics for Piloted Simulations
Abstract
Interactions between rotor wake, ship deck and ship airwake and/or varying wind fields may lead to substantial modifications to the rotor inflow distribution, producing rapidly changing forces and moments that affect the rotorcraft flight dynamics and handling qualities. Thus, maneuvers in vicinity of terrain andcomplex obstacles, such as landing and take-off on ship decks and offshore platforms, account for the most demanding and hazardous situations in rotorcraft operations. Better taking into account the abovementioned effects in pilot training simulators can be expected to improve pilot training for suchcritical situations, thereby reducing the risk of mishaps.Because of the extreme computational power requirements, real-time flow field simulations with the necessary spatial resolutions are not possible using high-fidelity (RANS based) CFD approaches. Lattice-Boltzmann methods (LBM) lend themselves to heavy parallelization, thus making them computationallyextremely efficient when GPU architectures are used to solve for a flow field and, therefore, they are attractive for real-time simulations. However, these methods have not yet been successfully applied to ship airwakes and never been used for rotorcraft aerodynamics simulations.In a proof of concept we showed that our fully-coupled LBM based approach performed similar or better (depending on the specific investigated pilot input and dynamic vehicle response) when compared to other methods currently being used in flight simulations, such as the Pitt-Peters inflow model. However, such widely-used models do not offer the versatility and the capabilities of the discussed model herein (in regard to the effects of a rapidly changing flow field or arbitrary surroundings), also including the added benefit of being independent of prior knowledge about the flow field (on the ship). In contrast to existingsimulation approaches that are encumbered by the need for look-up tables and preexisting measurements (e.g., of the ship airwake), boundary conditions are realized at simulation run-time. Therefore, the model is able to incorporate arbitrary dynamic obstacles, such as moving ship decks and superstructures, their effect on the flow field including rotor downwash, and any wake interferences (e.g., ship airwake with rotor wake) in real-time and without preexisting knowledge (other than the geometry of the environment).Furthermore, the introduced two-way coupling between the flow field aerodynamics and rotorcraft flight dynamics enables the feedback of any interactional flow field modifications to the flight dynamics and vice versa, making the model suitable for more realistic pilot-in-the-loop simulations, whereas current models do not accurately represent the aforementioned effects in real-time.After model development is finished, generic full-scale and reduced-scale aerodynamic and flight dynamic measurement data are used for validation purposes. The data IGE and OGE will be from literature, accessible test data, and from hover and wind tunnel tests to be performed under this program. Besides the objective to provide higher-fidelity aerodynamic modeling for more realistic pilot simulator training, another objective is to investigate significant couplings between fundamental flow physics in ground effect and rotor aerodynamics/dynamics, that are not yet well understood. This additional insight will also inform flight control system development.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 06, 2021
- Source ID
- N000142112021
Entities
People
- Juergen Rauleder
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy