Hypersonic laminar/turbulent transition: computations and experiments

In order to predict the laminar/turbulent transition on a hypersonic vehicle forebody at Mach numbers 4 and 6, the three-dimensional (3D) modal linear stability analysis is applied, coupled with the eN method. Nevertheless, N factors are unknown for wind tunnel conditions. Experimental investigations have been carried out on a flat plate in the blowdown wind tunnel T-313 of ITAM RAS (Novosibirsk). At M∞ = 2 to 6, the position of laminar/turbulent transition was measured by both Pitot tube and thermocouples. Then, stability analysis allows computing N factors at transition on the flat plate: they are about 3 ∼ 4, typical of conventional wind tunnels. These flat plate correlations can then be used to predict the transition on the forebody in the same wind tunnel. Experiments for the forebody are currently in progress and will allow checking the predicted transition location