Category: hydraulics

Refactoring the SWMM 5 Help File – Routing in SWMM5

Routing in SWMM5

Flow Routing

Flow routing within a conduit link in SWMM is governed by the conservation of mass and momentum equations for gradually varied, unsteady flow (i.e., the Saint Venant flow equations). The SWMM user has a choice on the level of sophistication used to solve these equations:… Read the rest

Peak Discharge: SCS Peak Discharge Method in Innovyze H2OCalc

Peak Discharge: SCS Peak Discharge Method

The dialog box for the SCS peak discharge method is shown below.

· Input for the SCS peak discharge method:

· Unit System – English or SI unit.

· Solving Target – Peak discharge or time of concentration.

· Equations – Rational method or … Read the rest

Energy Relation for Closed Conduit Flow in Innovyze H2OCalc

Energy Relation for Closed Conduit Flow

Conservation of energy involves a balance in total energy, expressed as head, between any upstream point of flow and a corresponding downstream point, including head losses caused by friction and the viscous dissipation of turbulence at bends and other appurtenances (i.e., form losses or … Read the rest

Pump Characteristic Curve from Innovyze H2OCalc

Pump Characteristic Curve

Pump Characteristic Curve

Pump characteristic curves are usually presented graphically describing the relationship between pump head, hp, and the flow rate, Q using either an exponential equation or 3-point quadratic form. The exponential pump characteristic curve is given as

where hc = the pump cutoff head … Read the rest

Inertia of Pumps and Motors from Innovyze H2OCalc – Idea for SWMM6

Inertia of Pumps and Motors

The combined inertia of pumps and motors driving them, including the connecting shafts and couplings, is required for transient analysis associated with the starting and stopping of pumps. The equations provided below are intended to be used as an initial guide to the inertia values … Read the rest

Gradually Varied Flow in Innovyze H2OCalc

3.4 Gradually Varied Flow

Discussions in the previous sections have focused on uniform flow hydraulics where flow depth y and flow velocity V remain constant along the channel. In this section, we consider gradually varied flow, which is a form of steady nonuniform flow characterized by gradual variations in flow … Read the rest

Flow Calculator (Simple in Innovyze H2OCalc) – Option for SWMM6?

2.3.1 Flow Calculator (Simple in Innovyze H2OCalc)

The Flow Calculator category performs hydraulic calculations for the following elements: Circular Channel, Rectangular Channel, Triangular Channel, Trapezoidal Channel, Irregular Channel, and Pressurized Pipe.

Circular Channel

The circular channel dialog box is shown below.

Input for circular channel:

  • Flow Unit – Select the
Read the rest

Water Hammer in Innovyze H2OCalc

3.14 Water Hammer

Surge analysis is important to estimate the worst-case events in the Water Distribution Systems (WDS). Transient regimes in WDS are inevitable and will normally occur as a result of action at pump stations and control valves. Regions that are particularly susceptible to transients are high elevation areas, … Read the rest

Moody Friction Factor Calculator from Innovyze H2OCalc

3.3 Moody Friction Factor Calculator

Darcy-Weisbach friction factor, f, can be evaluated in terms of equivalent sand grain roughness, e, and Reynolds number, Re. Reynolds number is a dimensionless ratio of inertial forces to viscous forces acting on flow and is defined for any cross-sectional shape as

For … Read the rest

Innovyze H2OCalc Head loss due to Transitions and Fittings (Local loss)

3.7 Head loss due to Transitions and Fittings (Local loss)

Whenever flow velocity changes direction or magnitude in a conduit (e.g., at fittings, bends, and other appurtenances) added turbulence is induced. The energy associated with that turbulence is eventually dissipated into heat that produces a minor head loss, or local … Read the rest

Urban Drainage Structures from Innovyze H2OCalc

3.13 Urban Drainage Structures

The methodology presented here for analysis and design of the drainage structures described in this section is based on HEC-22 manual (FHWA, 2001)

Gutter Flow

Gutters are the sections of roadway that run adjacent to the curb. Their purpose is to collect and convey surface runoff … Read the rest

General Culvert Information from Innovyze H2OCalc for All Culvert Programs

General Culvert Information from Innovyze H2OCalc for All Culvert Programs

A culvert is a pipe that carries water under or through some feature (usually a road or highway) that would otherwise block the flow of water. The culvert acts as an open channel as long as the flow is partly … Read the rest

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