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Hydraulics

2 tools in the Civil and Geotechnical area.

Open-Channel Flow

Steady flow in an open channel of rectangular, trapezoidal, triangular, circular (pipe partly full) or parabolic section by Manning's equation: normal depth for a discharge or discharge for a depth (bisection, iterations shown), critical depth, Froude number and flow regime, velocity, bed shear stress, critical slope, specific energy with the alternate depth and the E-y chart, the best hydraulic section (minimum wetted perimeter) for a discharge, the hydraulic jump from a supercritical depth by the momentum function of the actual section (conjugate depth, energy loss, power dissipated, jump form and the USBR length), the gradually varied flow profile from a control depth by the direct-step method (M, S, C, H and A classification, depth-distance table and chart), and weir discharge or head for sharp-crested rectangular (Kindsvater-Carter, Rehbock, Francis), V-notch (Kindsvater-Shen, the 90-degree Cone equation) and broad-crested weirs. Manning's n is picked from Chow's Table 5-6 or entered. The default case is Chow's trapezoidal channel (Open-Channel Hydraulics, 1959, Examples 6-2 and 10-1): 20 ft bottom, 2:1 sides, n 0.025, slope 0.0016, 400 ft³/s, giving a normal depth of 3.36 ft, a critical depth of 2.22 ft (energy coefficient 1.10) and the M1 backwater profile behind a dam that holds 5 ft of water, 2,375 ft long.

1 worked example reproduced, listed on the tool page.

Culvert and Storm Drain Hydraulics

Two tools of the FHWA drainage manuals. Culvert (HDS-5, 2012): a circular, box, elliptical or pipe-arch barrel with one of 22 inlet configurations; headwater by inlet control (the HDS-5 Appendix A weir and orifice equations with the transition between them) and by outlet control (entrance, Manning friction and exit losses with the critical-depth / (d_c + D)/2 rule), the controlling headwater, the outlet velocity, tailwater entered or from a downstream trapezoidal channel, roadway overtopping by the broad-crested weir equation with the HDS-5 discharge coefficients, and the performance curve of headwater against discharge with both controls and the road. Storm drain (HEC-22, 2009 / 2024): the Rational method with an IDF fit, time of concentration by the kinematic-wave sheet flow (or TR-55), shallow concentrated and channel segments, gutter spread by the Manning gutter equation (Izzard form, composite sections), grate and curb-opening interception with the splash-over velocities, pipe sizing for full flow by Manning along a trunk line with the cumulative CA and system time, inverts from the crown-drop rule, and the hydraulic and energy grade lines through the system by the FHWA access-hole energy loss method with the profile. Defaults: the HDS-5 Design Guideline 1 circular culvert (200 ft³/s, 54 in concrete pipe) and the HEC-22 Example 7-3 storm drain (four pipes, structures 40 to 44).

1 worked example reproduced, listed on the tool page.

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