Published online by Cambridge University Press: 04 July 2016
The effects of windtunnel constraint during low speed unsteady aerodynamic experiments are assessed by comparing the data from two Naca 0015 models, one with a chord length of half the other. Ramp-up and ramp-down tests are considered, to distinguish between the effects of constraint upon separation and attachment. The unsteady separation process measured in terms of the normal force, pitching moment and stall vortex convection speed, is virtually unaffected by the difference in constraint between the two models, whereas the attachment process, assessed in terms of the normal force response and attachment behaviour, is sensitive to the size of the model.