Numerical and Experimental Analysis of Low-Density Effects in Suborbital Flight of FAST20XX

Abstract

Subject of the present paper has been the experimental and numerical characterization of test chamber flow of DLR-V2G low-density wind tunnel, in the frame of EC FAST20XX project activities dedicated to the validation of numerical tools able to predict rarefaction effects in suborbital flight. Pitot pressure radial profiles measured at different positions downstream the test chamber have been compared at nozzle exit to numerical results obtained with different methodologies accounting for rarefaction effects (CFD with slip-flow boundary conditions, a hybrid CFD-DSMC procedure), and a re-definition of the V2G facility envelope in terms of flight-relevant parameters (Mach, Reynolds, Knudsen numbers) has been presented. A good agreement between experiments and numerical results has been achieved, thus confirming that the “actual” test chamber flow knowledge is of fundamental importance for a proper numerical rebuilding of an experimental test campaign.