INVESTIGATION OF THE EFFECTS OF ABLATION-INDUCED DISTRIBUTED ROUGHNESS ON SHOCK-WAVE/BOUNDARY-LAYER
Abstract
Hypersonic cruise vehicles and spacecraft that enter planetary atmospheres often employ ablative thermal protection systems (TPS). Many studies have shown that ablation can generate roughness, cross-hatching, and striations on a vehicle surface. Ablation is even more likely to introduce distributed roughness on a surface when employing complex three-dimensional woven composite materials, as the different components of the composite often ablate at different rates. The design of hypersonic systems is further complicated by the presence of shockwave/boundary-layer interactions (SWBLI). These interactions are a primary concern in the design of supersonic and hypersonic vehicles, as fins and control surfaces will generate shock waves that impinge on the boundary layer developing over the vehicle surface. SWBLI often lead to flow separation and are highly unsteady, leading to elevated local acoustic and thermal loads in the vicinity of the interaction that can cause vehicle damage or failure. Understanding the scaling and dynamic behavior of such interactions is therefore critically important for the design of future hypersonic systems. The complexity of these interactions, however, makes them difficult to model computationally. Moreover, almost all previous research into SWBLI flow physics has been performed over smooth surfaces, as an extensive literature survey revealed that there have been no prior investigations of SWBLI occurring over surfaces roughened via ablation using modern experimental techniques, and it is unclear what effect a representative TPS topology will have on the structure and dynamics of SWBLI. To address these issues the PI is proposing an experimental campaign that will employ real-world materials to study the effect of TPS roughness on the dynamic behavior of hypersonic SWBLI. Coupled with the deployment of a battery of modern diagnostic tools, this approach should reveal key insights into the nature of SWBLI.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 12, 2021
- Source ID
- FA95502010190
Entities
People
- Christopher Combs
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Texas at San Antonio