Longitudinal vortices have tremendous practical utility for flow control (control by vortices) and in some cases have exhibited tremendous potential for causing harm if uncontrolled (i.e. control of vortices is required). Vortex control has thus far been carried out via multitudinous approaches in an empirical fashion, aided by the essentially inviscid nature of much of longitudinal vortex behaviour. Further refinement and several applications of vortex flow control require knowledge regarding the detailed flow physics of longitudinal vortices such as transition, transitional flow regimes, turbulence structure and modelling, and interaction with shock waves, other vortices and surfaces. This paper summarises vortex control applications and extant techniques for the control of longitudinal vortices produced by bodies, leading edges, tips, and intersections.

A unified analytical method is presented for evaluating the generic buckling behaviours of simply-supported thick orthotropic cylindrical shells subjected to both axial compression and lateral pressure. The thick shell theory and Flugge type equations are employed. The equilibrium equations of shells become particularly simple in the chosen space by considering an appropriate transformation and utilizing some previous material constant definitions due to Brunelle. Hence, comprehensive solutions are found to this problem so that the curves presented in the text are generic rather than specific. The analysis is for the restricted case of a single homogeneous layer. The effects of various parameters on buckling loads are studied. The results indicate that the buckling coefficient increases with increasing generalised rigidity ratio D* but decreases with increasing generalised Poisson's ratio ε. The results of a reduced set of equations agree with those obtained by previous investigators.

This paper considers the dynamic stall vortex of importance in helicopter rotor aerodynamics and discusses previous measurements of its convection speed. It emerges that an anomaly exists between the available data sets, i.e. that some workers find that the convection speed is dependent upon the aerofoil motion, while others find that this is not the case. Measurements of the convection speed from data gathered at Glasgow University for a variety of aerofoil shapes and motion types are then presented, which support the conclusion that the dynamic stall vortex convection speed is independent of aerofoil type and motion type to a first order.