- Multiple Choice A Water Tunnel Supplies An Incompressible Uniform Stream Of Velocity U At The Inlet Of Its Test Secti 1 (102.82 KiB) Viewed 32 times
(Multiple choice) A water tunnel supplies an incompressible uniform stream of velocity U, at the inlet of its test section, as shown in figure 5. The walls of the water tunnel are hydrophobic so boundary layers do not form due to negligible wall friction. To find the drag on a bluff body located at y = 0, the velocity profile in the wake is measured to exhibit a gaussian profile in the y-direction with a constant shift U2, i.e u(y) = U2 - e-y? For the relation between U, at the inlet and U2 in the wake, which one of the following is true? (a) U2 <Ui; (b) U2 = U1 ; (c) U2 > U1; Note the gaussian function e-y? > 0 for all y and rapidly decays to zero with increasing lyl. Ui UI U U2 U2 U2 TIWIT water tunnel experiment (a) U2 <UL (b) U2 = U1 (c) U2 > U