Computation of radiative and convective contributions to Viking afterbody heating

This paper investigates the hypothesis that the observered gap between CFD and -derived flight measurements for afterbody heating of the Viking spacecraft be accounted for by infrared radiation from CO2 molecules in the wake flow. The DLR code is implemented to simulate the Viking I spacecraft at an altitude of 37.4km on a flow-adapted hybrid 3D grid with radiation- flowfield coupling. The radiation spectrum of CO2 molecule is represented by a statistical narrow band model and radiation transport calculated via an opacity-binned ray-tracing model. The calculated total heating level on aluminium base cover is in good agreement with the flight data, while the total heating for the fiberglass cover is overpredicted. Furthermore, radiation-flowfield coupling is to reduce the total heat flux on the vehicle surface by up to 10% compared to when is treated in an uncoupled manner.