Question

Standard USBR stilling basin-II is useful for energy dissipation at the bottom of the overflow structure, if the approaching Froude number is ________________

(a) less than 4.5

(b) more than 4.5

(c) less than 2.5

(d) more than 2.5

I got this question during an interview for a job.

I need to ask this question from Energy Dissipation Below Overflow Spillway in portion Spillways, Energy Dissipators and Spillway Gates of Irrigation Engineering

Answer 1

The correct answer is (b) more than 4.5

The explanation: USBR has standardized stilling basins for different Froude numbers. USBR stilling basin- II is recommended for large structures when the Froude number is more than 4.5. The dissipation of energy will be 45 to 85%.