Mach number dependence of laminar near-wake transition for slender cones

The paper describes a correlational study based on data in the literature on laminar near-wake transition for sharp slender cones obtained in ballistic range experiments. It is shown that the apparent Mach number dependence of the laminar wake transition process can be explained with the use of axis-based fluid properties. A nearly universal axis-based transition Reynolds number independent of Mach number is found. It is defined as the axial near-wake velocity defect after pressure relaxation but before momentum diffusion occurs, multiplied by the transition distance divided by the axis viscosity. A supersonic laminar wake will undergo transition in the near wake of a slender cone at a value for this universal Reynolds number of about 80,000. An approximate method for computing the axis properties is described.