A laboratory wind tunnel has a test section \(25 \mathrm{~cm}\) square and \(50 \mathrm{~cm}\) long. With nominal air speed \(U_{1}=25 \mathrm{~m} / \mathrm{s}\) at the test section inlet, turbulent boundary layers form on the top, bottom, and side walls of the tunnel. The boundary-layer thickness is \(\delta_{1}=10 \mathrm{~mm}\) at the inlet and \(\delta_{2}=30 \mathrm{~mm}\) at the outlet from the test section. The boundary-layer velocity profiles are of power-law form, with \(u / U=(y / \delta)^{1 / 7}\). Evaluate the freestream velocity, \(U_{2}\), at the exit from the wind-tunnel test section. Determine the change in static pressure along the test section.