Joint Computational-Experimental Investigation of Fin-Wake FlowInteractions
Abstract
The wake of slender supersonic projectiles displays complex physics associated with multiple shear layers and shock waves interacting with each other at different relative spatial orientations. In the simplest case, empennage shear layers over the fuselage intrude approximately orthogonally on the primary base flow shear layer interaction. In the more general case of non-zero angle of attack or yaw, an additional fin-induced swept shock-turbulent boundary layer interaction arises; the associated vortical structure of significant strength and lambda-shock further interfere with the development of the wake. Although fundamental research has examined many individual components of the problem, their combined manifestation includes highly non-linear phenomena that have remained unex- plored. The present effort fills this gap through a comprehensive and systematic procedure lever- aging closely synergized experiments and simulations focused on three-dimensional (3D) fin-wake interactions The evolution of spatio-temporal scales of different coherent structures, and their breakdown, will be examined to highlight excursions to the much-examined nominal base flow by the swept fin-induced lambda-shock, 3D vortical structures arising from open separation and vari- ous secondary features such as tip and corner vortices. Emphasis will be placed on low frequency unsteadiness with potential to elicit a structural response, underlying causes rooted in instabilities and wave phenomena, development of Reynolds stresses and associated loads. A methodical strategy will be pursued: starting from a simple configuration highlighting the primary shear layer, the complexity will be successively escalated to include the effects of the fin and associated shocks. The campaigns will cover a broad parameter space in terms of Mach and Reynolds numbers and shock induced interaction strength. The experimental campaign will em- ploy high bandwidth diagnostic and advanced time-resolved laser-based techniques. The simula- tions will use different levels of fidelity ranging from Reynolds-Averaged Navier-Stokes equations to wall-resolved Large Eddy Simulations. The data will be analyzed with a variety of traditional and modal data-driven and physics-informed procedures. The compounding effects associated with fin-wake interactions provide a uniquely rich envi- ronment to study the pertinent fluid dynamics. Our approach constitutes natural building blocks to isolate key phenomena in a canonical setting. The generated insights will highlight their poten- tial flow sensitivity and form the basis for future development of scalable control strategies. The diagnostics and numerical techniques to be deployed are at the cutting-edge for high-speed flows; this effort will further advance these in new ways to aid other ongoing and future efforts. The joint experimental-simulation strategy also lays the foundation for workforce training; the close coordi- nation ensures that students in each thrust understand the strengths and limitations of the other and develop collaboration and complex problem solving skills necessary in the applied (ÔrealÕ) world.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 28, 2023
- Source ID
- W911NF2310184
Entities
People
- Farrukh S. Alvi
Organizations
- Army Contracting Command
- Florida State University
- United States Army