The Potential of Ultrasonically Absorptive TPS Materials for Hypersonic Vehicles

Abstract

The potential of ultrasonically absorptive carbon fiber reinforced carbon (C/C) based materials for passive boundary layer transition control on hypersonic flight vehicles is investigated. Based on previous studies on C/C, optimized C/C based materials are developed and studied with respect to their temperature stability and ultrasonic absorption properties at hypersonic flight regimes of interest. Generic vehicle shapes providing an essentially two dimensional flow field allowing the second mode instability to be the dominant boundary layer instability are studied using an engineering approach. Furthermore, the study provides an overview on the test procedures established in DLR to assess the ultrasonic absorption properties of porous materials and to experimentally investigate the impact of potential candidates on the boundary layer transition process.