An understanding of beam tube motion as a function of wind speed is important in predicting scattering noise from the beam tube baffles and in deciding if we need to re-insulate the beam tube. This data was taken during the windstorm on Apr. 11, 2015 at baffle #96 (near the power maximum for the diffracted light from the pattern on the original optics), near the first double doors towards the CS from MY. Figure 1 is a photo of the accelerometers attached to the beam tube, and Figures 2-4 show the motion along the different axes at 3 different wind speeds (9, 18 and 24 MPH). As a first guess I would expect peak amplitudes to increase roughly with wind speed to the 3/2 power (wind power goes as the cube), and, very roughly, it seems consistent.
