Kevin Horton said:The whole thing was a complete waste of time, as the additional roughness from the tape and yarn changed the airflow, and the problem we were trying to diagnose wasn't there when the tufts were on. It came back as soon as the tufts and tape were removed.
We maybe should have tried again with thinner tape to hold the tufts on - clear packing tape? Maybe the thinner tape wouldn't have tripped the boundary layer, and allowed us to confirm the vortex shedding we suspected was occurring.