An alternative scheme for using the velocity probe described in Problem 9.5 is to place it in the middle of the pipe, where the velocity is expected to be 2.0 times the average velocity. Compute the amount of insertion required to center the probe. Then, if the accuracy of placement is again plus or minus 5.0 mm, compute the possible error in measuring the average velocity.
Problem 9.5
A small velocity probe is to be inserted through a pipe wall. If we measure from the outside of the DN 150 Schedule 80 pipe, how far (in mm) should the probe be inserted to sense the average velocity if the flow in the pipe is laminar?