High-fidelity numerical simulation of unsteady aerodynamics at high Reynolds number with application to the control of tailless aircraft
Abstract
The proposed effort will implement several new mathematical techniques in to an existing immersed boundary code with the intent of simulating separated flow fields on a UCAV configuration at wind tunnel Reynolds numbers. The existing code uses a novel formulation that limits the number of far-field data points required to resolve the flow field. Extending immersed boundary methods to higher Reynolds numbers requires implementing refined meshes near the boundary. To keep the computational costs down the grids must be adaptive, and the proposed effort will start with this implementation. The code will then be modified to use an LES formulation for resolving the turbulent flow ~ two approaches will be used here a stretched-vortex approach (superposition of stretched vortices by the resolved strain field ~ analytical solution for stretched vortex) and a wall-modeled one. The new simulation capability will be deployed in the study of active flow control applied to a UCAV configuration, and will use stability analyses to determine optimal control strategies. Although this latter effort will be undertaken a lower Reynolds numbers, it is expected that the results will have applicability at higher Reynolds numbers.In the area of unsteady aerodynamic phenomena, we have selected several proposals that focus on two areas key to advancing the Navy~s sea-based aviation emphasis. The first of these has to do with the nature of the turbulence that exists in a ship airwake. At full-scale, this flow field is impacted by many factors including WOD angles, ship motion, and the atmospheric boundary layer. To attempt to tackle all of these factors in a single dynamically-scaled experiment is not possible. There are, however, important insights that can be gained by exploring individual elements of these flows in a basic research setting, and we have selected proposals with this in mind. The second area has to do with the aerodynamic response of a vehicle transiting through the ship airwake. Here, we are interested in the unsteady aerodynamic response of the wing, existing conventional and notional future concepts, to a flow field transient. Clearly, the first area will inform the second with regard to the nature of the transient that will be encountered. Initially, though, shear flows and coherent vortical structures will be taken as model flows.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 23, 2016
- Source ID
- N000141612734
Entities
People
- Tim Colonius
Organizations
- California Institute of Technology
- Office of Naval Research
- United States Navy