Abstract:

ESDU 93024 summarises situations where vortex generators have been used to control shock-induced separation. It is suggested that their use should be considered at the design stage and not only as a fix for undesirable characteristics found post-flight. Types of vortex generators are reviewed and the aerodynamic principles of their operation considered. Attention is focussed on vane types: co- or counter-rotating and biplane. By applying simplifying assumptions, the degree and range of mixing effectiveness, and the rate of vortex decay, are studied and offer some guidance on the streamwise extent of control, the lateral spacing and the height above the surface that are appropriate for both co- and counter-rotating types. The degree of control achievable on aerofoils is considered, and calculations also show the possible adverse effects on drag. The use of multiple arrays and the use of vortex generators to control shock-induced separation in corners are briefly discussed. The use of wind-tunnel tests to assess the effects of vortex generators is considered.