Heated Cloud Rise Model

The rise of launch clouds to stabilization is forced by an altitude varying distribution of momention and buoyancy (temperature). In most of the plume, the temperature excess over that of the atmosphere is large and the buoyant force accelerates the launch products to "high" altitudes. The acceleration is retarded by the exhaust velocity, but augmented strongly by water vapor phase changes and possibly by heat release from residual chemistry. Turbulent diffusion of the buoyancy with or without wind shear and atmospheric temperature gradients stop the flow above the neutral buoyancy level; the flow falls back and the cloud is transported within the prevailing weather. The cloud may be toxic. We develop a first-principle computational capability centered on a proven cloud formation code (PSR/2DSALE). A tailored grid with variable vertical resolution based on specific launch profiles is proposed, and we develop a distributed buoyancy and momentum source function based on the "ground" cloud and standard plume flowfield. We plan a test calculation matrix with stable and unstable atmospheres, high and low moisture profiles, and wind shear. We add PSR's multicomponent first-principle microphysics code to account rigorously for particle growth in the plume and cloud. Extension to a Phase II 3-D capability is planned.