Numerical Investigation of Laminar to Turbulent Boundary Layer Transition Over Airship Envelopes

The shape of a conventional airship’s envelope is usually an axisymmetric body of revolution. Previous numerical and experimental studies have indicated that at zero angle of attack, the flow over such shapes is either fully turbulent or transits from laminar to turbulent at nearly half of the envelope’s length. In most numerical investigations of such bodies, k-ɛ or k-ω-SST turbulence models are used. In recent studies, a four-equation k-ω SST-LM transition turbulence model has been proposed and shown to predict transition on a flat plate quite well. In this study, the transition of the laminar boundary layer to the turbulent boundary layer over the bodies of revolution of airship envelopes is investigated using the k-ω SST–LM transition turbulence model. The results obtained in numerical analysis are validated with the data available in the literature. It is seen that the two-equation k-ω SST turbulence model is not able to capture the laminar to turbulent transition, whereas the four-equation k-ω SST-LM transition turbulence model can capture it quite well.