Circular

Given:

• theta = interior angle in radians
• d = diameter
• y = depth

In computing the theta for circular sections, there are three conditions to deal with.

The maximum flow capacity in circular sections occurs at a depth of 0.938 times the diameter, however, it is common to design circular conduits to carry maximum flows when flowing full at 100% of the diameter. Wave action and irregularities make it difficult to maintain flows at 0.938 times the diameter for very long. The flow is unstable at that depth.