File:HY8image21.jpg

Straight drop structures.

Variables from the figure

• y_c — Critical depth
• h₀ — Drop from crest to stilling basin floor
• h — Vertical drop between the approach and tailwater channels
• y₁ — Pool depth under the nappe
• y₂ — Depth of flow at the tow of the nappe or the beginning of the hydraulic jump
• y₃ — Tailwater depth sequent to y2
• L₁ — Distance from the headwall to the point where the surface of the upper nappe strikes the stilling basin floor
• L₂ — Distance from the upstream face of the floor blocks to the end of the stilling basin
• L₃ — distance from the upstream face of the floor blocks to the end of the stilling basin
• L_B — Stilling basin length