A Pitot tube is fixed in a main of diameter 25 cm and the difference of pressure indicated by the guage is 6 em of water column. Find the volume of water passing through the main in two minutes ?

Explanation

Pitot tube is shown in Fig. The aperture A is parallel to the flow whereas B is facing the flow. At B the ki- Cl netic energy per unit volume is reduced from `1//2 rhov^(2)` to zero - where is the velocity of flow. Hence pressure increases and water rises to a higher level.
` (1)/(2) rho v^(2) = hrho g, v = sqrt( 2gh ) `
` h= 0.0 6 m `
` v= sqrt( 2 xx9. 8 xx 0.06) `
Rate of flow `= av = pi r ^(2) v `
Volume of water flowing in two minutes ` = pi r^(2) v xx ` time
` = 3.14 xx (0.125)^(2) xx sqrt( 2xx9.8xx 0.06) xx 2 xx 60`
`= 6. 3846 m ^(3)`