Structural Mechanics

A student can measure free-stream velocity of a low-speed wind tunnel using a i. Pitot tube alone aligned with the flow direction. ii. Pitot tube aligned with the flow direction with static pressure measurement at an appropriate position on the tunnel wall. iii. Pitot tube aligned with the flow direction along with barometer pressure reading of the outside ambient. iv. Pitot static tube alone aligned with the flow direction. Considering the above statements, which of the following options is correct? (A) (i) only (B) (i) & (ii) (C) (ii) & (iv) (D) (i), (iii) & (iv)