A laboratory wind tunnel has a test section 25 cm square and 50 cm long. With nominal air speed U1 =25m=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 δ1 =10 mm at the inlet and δ2 =30 mm at the outlet from the test section. The boundary-layer velocity profiles are of power-law form, with u=U =ðy=δÞ1=7. Evaluate the freestream velocity, U2, at the exit from the wind-tunnel test section. Determine the change in static pressure along the test section.

An engine, weighing 3000 n, is supported on a pedestal mount. it has been observed that the engine induces vibration into the surrounding area through its pedestal at the maximum operating speed. determine the stiffness of the dynamic vibration absorber spring in (n/m) that will reduce the vibration when mounted on the pedestal. the magnitude of the exciting force is 250 n, and the amplitude of motion of the auxiliary mass is to be limited to 2 mm note: in this question type-in right numbers, no decimals, no fractions, no unit. approximate to right number if needed