# Structure Loss methods supported by each solver

 Product(s): CivilStorm, SewerCAD, SewerGEMS, StormCAD Version(s): Select Series 3, Select Series 4, Select Series 5 and Connect Edition Area: Layout and Data Input

# Overview

OpenFlows Storm and Sewer products have been supporting several Structure Loss methods with the release of each version. This article explains which methods are supported by each solver and version.

Absolute - The user will enter the exact head loss in feet or meters.

Standard
- The user will enter the standard headloss coefficient K. The headloss will then be calculated based on the formula: headloss = K*V^2/2g. The standard method calculates structure headloss based on the exit pipe's velocity. The exit velocity head is multiplied by a user-entered coefficient to determine the loss. For numerical stability reason an empirical velocity filter is used when the velocity is larger than 5.0 ft/s as follows: v’ = 5.0 + 0.1*(v -5.0)

Generic
- The generic method computes the structure headloss by multiplying the velocity head of the exit pipe by the user-entered downstream coefficient and then subtracting the velocity head of the governing upstream pipe multiplied by the user-entered upstream coefficient.

HEC-22 Energy (2nd Edition) and HEC-22 Energy (3rd Edition)
- this is the standard HEC-22 headloss method, which correlates structure headloss to the velocity head in the outlet pipe using a coefficient, which accounts for several factors such as benching, plunging, diameter, etc. This method was changed between the two latest editions of the HEC-22 manual.

AASHTO
- this is based on power-loss methodologies, which accounts for contractions, expansions and bends.

- this method allows you to enter a rating table of flow versus headloss across the structure.

# Methods Supported for Each Solver and Version

CONNECT EDITION

 Solvers Generic (K) Absolute Standard Hec-22 Energy 2nd Edition Hec-22 Energy 3rdEdition AASHTO Flow Headloss Curve Hec-22 Minor Loss Implicit Y Y Y Y N N N N Explicit N Y Y N Y N N N Convex Y Y Y Y Y Y Y Y Rational Y Y Y Y Y Y Y Y

V8i SELECT SERIES 5

 Solvers Generic (K) Absolute Standard Hec-22 Energy 2nd Edition Hec-22 Energy 3rdEdition AASHTO Flow Headloss Curve Hec-22 Minor Loss Implicit Y Y Y Y N N N N Explicit N Y N N N N N N Convex Y Y Y Y Y Y Y N Rational Y Y Y Y Y Y Y N

V8i SELECT SERIES 4

 Solvers Generic (K) Absolute Standard Hec-22 Energy 2nd Edition Hec-22 Energy 3rdEdition AASHTO Flow Headloss Curve Hec-22 Minor Loss Implicit Y Y Y Y N N N N Explicit N Y N N N N N N Convex Y Y Y Y Y Y Y N Rational Y Y Y Y Y Y Y N

V8i SELECT SERIES 3

 Solvers Generic (K) Absolute Standard Hec-22 Energy 2nd Edition Hec-22 Energy 3rdEdition AASHTO Flow Headloss Curve Hec-22 Minor Loss Implicit Y Y Y Y N N N N Explicit N Y N N N N N N Convex Y Y Y Y Y Y Y N Rational Y Y Y Y Y Y Y N