Evaluating Shock-Tube Informed Biases for Shock-Layer Radiative Heating Simulations
Christopher O. Johnston
Abstract
A methodology for directly informing flight vehicle radiative heating simulations based on shock-tube measurements is developed. The differences between these shock-tube informed (STI) radiative heating values and the corresponding nominal values are typically the dominant contributor to the radiative heating margin. Previous approaches for evaluating the STI radiation were limited to the stagnation-point radiative flux, assumed optically thin adjustments to the radiative flux, and were limited to tangent-slab radiation transport. The present approach removes these limitations. This approach relates differences between shock-tube measurements and their nominal simulations to the upper-level number density of individual radiative processes. These upper-level number density differences are compiled as a function of time behind the shock for all relevant shock-tube measurements. These differences in the upper-level number density are then mapped to a vehicle flowfield using a streamline mapping approach. This mapping is applied during the radiation calculation to obtain the shock-tube informed bias to the radiative heating. By adjusting the upper-level number density prior to the radiative transport evaluation, the impact of optical thickness is captured. This approach may be automated within a flowfield and radiation code to enable routine analyses of the shock-tube informed biases.