Flow through a sudden contraction is shown. The minimum flow area at the vena contracta is given in terms of the area ratio by the contraction coefficient [32],

\[C_{c}=\frac{A_{c}}{A_{2}}=0.62+0.38\left(\frac{A_{2}}{A_{1}}\right)^{3}\]

The loss in a sudden contraction is mostly a result of the vena contracta: The fluid accelerates into the contraction, there is flow separation (as shown by the dashed lines), and the vena contracta acts as a miniature sudden expansion with significant secondary flow losses. Use these assumptions to obtain and plot estimates of the minor loss coefficient for a sudden contraction, and compare with the data presented in Fig. 8.15.

Data From Fig. 8.15

A Flow P8.81 Ac A2