NICOP - Rotorcraft Downwash and Dynamic Interface Modeling for Real-Time Simulations in Naval Applications
Abstract
Rotorcraft Downwash and Dynamic Interface Modeling for Real-Time Simulations in Naval Applications:The goal of this project is to study the complex aerodynamic interactions between rotorcraft downwash and the surface during take-off and landing, by developing a high-fidelity CFD model and validating it with recorded data. Interactions between the rotor wake and ship airwake and/or varying wind fields may lead to significant changes in the rotor inflow and affect the rotorcraft s flight dynamics and stability. As a result, the control and handling expected by the pilot can change considerably. In some cases altered flight dynamics of the rotorcraft can be a serious safety risk during take-off and landing. Current models do not include the effect of wake interferences on the inflow of the rotor, and do not represent well the coupled aerodynamic phenomena that govern the flight dynamics. Consequently, the combined effects of the rotor downwash, ship airwake, environmental wind airflow, take-off/landing surface 3D geometry, rotor inflow, and rotorcraft flight physics, on the stability of the rotorcraft are not well understood. The behavior and handling of the rotorcraft remains unpredictable in many scenarios with demanding take-off or landing conditions. The innovative S&T proposed in this project is the high-fidelity modeling and analysis of coupled ship/rotorcraft dynamic interface, including feedback to the rotor inflow. This will be enabled by the use of a specialized CFD solver recently developed at the Technical University of Munich, based on the Lattice-Boltzmann method suitable for parallel computing. In this approach, the microscopic motion of simulated fluid particles is integrated to satisfy Navier-Stokes equations by approximating the gas particle continuum with a set of weighted velocity distributions. In each step of the simulation, the momentum exchange between gas particles is locally and independently computed for each grid cell, and results are propagated to other cells in the direction of velocity distributions. Dynamic parameters related to the rotorcraft and its flight state are computed for the entire flow field, using discretized boundary conditions. Owing to its parallel processing properties, this method will enable very fast computations, and will allow real-time results using Graphical Processing Units (GPUs). The model will be validated using established databases of 3D ship structure and motion, and data from the ongoing rotor/ship airwake interaction measurement program conducted by the research team at the U.S. Naval Academy and George Washington University (USNA/GW).This model and the associated study will be valuable to the Navy in various ways. Aerodynamic flow and flight stability insights gained from this study can be used to guide the field use of existing rotorcraft and the design of new ones. The model~s postprocessing and visualization steps can be used to analyze moving objects or particle motions for brownout or whiteout simulations. And the real-time computation capability of the model can be leveraged to augment Navy pilot training simulations with higher fidelity responses and more representative simulated effects in scenarios involving take-off/landings on moving ships, under ambient winds, and with other aircraft and ship structures in close proximity.This proposal has been coordinated with Judah Milgram, in Code 35. He is particularly interested in this project and he will provide 50% co-funding.Desired outcomes are the high-fidelity model and fast simulation using the Lattice-Boltzmann method, the validation against recorded data, results of the analysis with varying input parameters, and publications in serious journals and conferences.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 23, 2016
- Source ID
- N629091612118
Entities
People
- Juergen Rauleder
Organizations
- Office of Naval Research
- Technische Universität Ilmenau
- United States Navy