Approximate entropy layer swallowing model for the engineering level aero thermodynamics code CBAERO

An approximate model is presented to include the effects of entropy swallowing 011 the turbulent heating on three dimensional bodies in hypersonic flow. Entropy layer swallowing in the boundary layer occurs when the boundary layer swallows the entropy layer formed as the streamlines passed through the normal and curved sections of the bow shock. The approach, based 011 the work of Dejarnette and Hamilton, estimates the shock shape and compares the mass flow the boundary layer with that of streamlines passing through the bow shock. The entropy at the edge of the boundary layer is then determined by tracing the edge streamline back to it's passage through the bow shock. This new estimate of the edge entropy is then used to adjust the edge conditions used in the approximate engineering level convective heating models. This approach has been implemented in the engineering level aerothermodynamic tool CBAERO. Comparisons of the present method are made to high fidelity CFD for both capsule and lifting body configurations, entering both the Earth and Mars atmospheres.