A DEMONSTRATION OF THE EFFECT OF THE TESTING ENVIRONMENT ON UNSTEADY AERODYNAMICS EXPERIMENTS

The effects of windtunnel constraint during low speed unsteady aerodyn amic 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-d own tests are considered, to distinguish between the effects of constr aint upon separation and attachment. Tle unsteady separation process m easured in terms of the normal force, pitching moment and stall vortex convection speed, is virtually unaffected by the difference in constr aint between the two models, whereas the attachment process, assessed in terms of the normal force response and attachment behaviour, is sen sitive to the size of the model.