Direct numerical simulation of hypersonic boundary layer transition over distributed surface porosity
Abstract
Carbon-fiber-reinforced carbon-ceramics (C/C) are a popular choice in hypersonics due to theirexcellent thermal resistance and low density. Additionally, their inherent porous structure can beexploited to integrate various flow-control strategies, such as transpiration cooling, CO2 injectionand passive attenuation of instability waves. The proposed work aims at developing a firstprinciples-based modeling technique to accurately account for the hydrodynamic and acousticeffects (at the basis of such controls) associated with the small-scale distributed anisotropicsurface porosity typical of C/C surfaces, dictated by the orientation and spacing of the carbonfiberplies.The proposed effort relies on high-resolution tomography and statistical volumetric porosity dataextracted from a real C/C sample, made available to Dr. Scalo’s group by DLR-Stuttgart. Thedevelopment of a new stochastically distributed surface permeability model to be applied indirect numerical simulations is discussed. Two flow scenarios are considered: (1) second-modewave amplification, in its later stages of evolution, over realistic C/C porosity as observed byWagner and co-workers (DLR-Göttingen); (2) sensitivity of cross-flow waves to carbon fiberorientation, and, hence, surface porosity distribution.The proposed effort provides a missing interface between materials and aerodynamics, enablingthe interdisciplinary design and analysis of C/C porous surfaces for flow conditions of interest tothe Air Force, extending their applicability to multiple flow control strategies. This goal isfacilitated by the creation of a new subtask dedicated to C/C materials already in program withinthe 2018-2022 NATO AVT-240 effort on Hypersonic Transition.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 09, 2018
- Source ID
- FA95501810292
Entities
People
- Carlo Scalo
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Virginia