Question

# a. In a few sentences, concisely explain the following concepts. i.Free surface ii. No-slip condition iii. Bedload iv. Suspended load v. Shear stress vi. Fluid element vii. Fluid streamlines viii.

Boundary Layer b. The diagram below, which shows streamlines around a cylinder as viewed from above, is annotated with numbers 1- 7. Write down which number represents the following regions and why: i.Flow stagnation, maximum pressure. ii. Decreasing velocity, increasing pressure. iii. Increasing velocity, decreasing pressure. iv. Undisturbed velocity and pressure. v. Increasing pressure, decreasing velocity, boundary layer separation. vi. Turbulent wake region. vii. Maximum velocity, minimum pressure. c. In designing a tall structure, you require knowledge of what the stagnation pressure and drag force is on the side of the structure that is facing a prevailing wind of average maximum velocity U = 4 m/s. The kinematic viscosity v of air at 20°C is 1.516 105 m2/s. Point 1 is far upstream of the structure where U = 4 m/s, p = 1.225 kg/m3, and P1 = 101.325 kPa. The drag coefficient of the structure is Ca = 2.0 (square structure). The air flows over a flat surface towards the structure (see diagram below). The distance between point 1 and 2 is 40 m. The height of the structure is 80 m, and the width b = 25 m i.The height of the turbulent boundary layer at point 2. ii. The stagnation pressure at point 2. iii. The drag force on the structure

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