Aerodynamic effects of Descent Rate and Deck Conditions on VTOL Dynamics
Abstract
Short take-off and vertical landing (STOVL) aircraft are essential assets of aircraft carriers, whose runway lengths are very short. Vertical landing is a particularly complex maneuver, during which two vertically oriented dissimilar jets are used to guide the aircraft towards the landing deck. Deck surface impingement of the two jets, and their mutual interaction, causes numerous adverse effects, including loss of lift, ingestion of hot gases by the inlet, acoustic and thermal loads on the airframe and extreme noise levels among others. These effects have their roots in the complex turbulent flowfield between the aircraft and the deck surface. In thepresent work, we explore the phenomena of lift loss due to suck-down at finite rates of descent, and the influence of boundary layers developing over the carrier deck; both are important problems which have received relatively little fundamental research attention. We build upon our extensive prior studies of the problem under hover conditions. We emphasize particularly the importance of the fountain flow that forms between the jets and interacts with the undersurface of the aircraft, the ground sheet that forms radially upon impingement, and the wind-over-deck boundary layer effects with and without distortion associated with obstacles such as the ship superstructure. We seek to connect the phenomenological observations to the underlying feedback and instability mechanisms under hover conditions i.e., their dynamic modulation by descent rates and wind-over-deck interference. A carefully organized prudent testmatrix is proposed for execution with a methodical, integrated and complementary experimental-computational strategy, bringing to bear advanced pointwise, planar and volume-based diagnostics and multi-fidelity simulations ranging from Reynolds-Averaged Navier Stokes to scale-resolved Large-Eddy Simulations. The results will yield benchmark quality high-fidelity spatio-temporally resolved databases, which will beprocessed with tradi- tional and recently developed data- and physics-driven processing tools that have proven their effectiveness in the hover problem. Workforce training will be a natural product of this effort, since graduate students will develop collaboration and complex problem solving skills necessary in the applied (#real#) world.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312366
Entities
People
- Farrukh S. Alvi
Organizations
- Florida State University
- Office of Naval Research
- United States Navy