TABLE OF CONTENTS The hydraulic jump equations were discussed in Chapter 2. To determine the jump location in a channel, we need to use the jump equation along with the gradually-varied flow calculations. The jump length is usually negligible compared to the length of a channel. Therefore, we often perform these calculations assuming that the jump occurs vertically. The flow depths, y J 1 and y J 2, just upstream and downstream of the jump should satisfy the jump equation. If there is gradually-varied flow upstream of the jump, y J 1 should also satisfy the gradually varied equations upstream. Likewise, if there is gradually varied flow downstream, then y J 2 should also satisfy the downstream gradually-varied flow equations.
EXAMPLE 4.6 Determine the distance between the hydraulic jump and the downstream end of channel 1 in Example 4.2.
We have already determined, in Example 4.2, that a hydraulic jump will occur in channel 1 followed by an S1 profile as in Figure 4.9a. We also determined that, based on the hydraulic jump equation, y J 2 = 4.13 ft, and therefore the S1 curve extends from an upstream depth of 4.13 ft from the jump location to a depth of 6.41 ft at the downstream end of channel 1.
To determine the jump location, we perform the gradually-varied flow calculations starting with a downstream depth of 6.41 ft. We will continue until we reach the upstream...
