BLAYER User Guide

Estimation of boundary layer edge or thickness is an essential aspect of utilizing high fidelity aerothermodynamic flow solutions. For viscous flow over a flat plate, the boundary layer thickness is usually defined as the distance from the wall at which the flow velocity (zero at the wall) has increased through some profile to 99% or 99.5% of the free stream velocity. In real gas flows over aerospace vehicles, a total enthalpy profile is employed for edge calculations. The importance of knowing boundary layer thickness and its relation to possible transition from laminar to turbulent flow is illustrated by Space Shuttle mission STS-114, when the appearance of tile gap filler protrusions on the nose was deemed serious enough that a crew member was called upon to exit the vehicle and remove the potential threat prior to its descent from orbit.

The BLAYER utility used as part of post-processing Orion/MPCV flow solutions is a generalization of the earlier BLAYER_RESULTS utility developed following the STS-107 Columbia accident. BLAYER handles a variable number of gas species (not just 5), allows for more than one temperature and for optional extra flow quantities, and omits optional handling of Orbiter tile datasets.