forcmain.c File Reference

Force-main friction and hydraulic calculations. More...

#include <math.h>
#include "headers.h"

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Macros
#define	_CRT_SECURE_NO_DEPRECATE

Functions
double	forcemain_getEquivN (int j, int k)
	Computes a Mannng's n that results in the same normal flow value for a force main flowing full under fully turbulent conditions using either the Hazen-Williams or Dary-Weisbach flow equations.
double	forcemain_getRoughFactor (int j, double lengthFactor)
	Computes an adjustment factor for a force main that compensates for any artificial lengthening the pipe may have received.
double	forcemain_getFricSlope (int j, double v, double hrad)
	Computes the headloss per unit length used in dynamic wave flow routing for a pressurized force main using either the Hazen-Williams or Darcy-Weisbach flow equations.

Detailed Description

Force-main friction and hydraulic calculations.

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com (OpenSWMM maintenance and extensions)

Copyright

Copyright (c) 2026 Caleb Buahin. OpenSWMM contributions only; original EPA SWMM credits are retained.

License

Apache-2.0 for OpenSWMM contributions; original EPA SWMM provenance is retained.

Macro Definition Documentation

_CRT_SECURE_NO_DEPRECATE

#define _CRT_SECURE_NO_DEPRECATE

Function Documentation

forcemain_getEquivN()

double forcemain_getEquivN	(	int	j,
		int	k )

Computes a Mannng's n that results in the same normal flow value for a force main flowing full under fully turbulent conditions using either the Hazen-Williams or Dary-Weisbach flow equations.

Parameters

[in]	j	Link index.
[in]	k	Conduit index.

Returns

An equivalent Manning's n for a force main.

forcemain_getFricSlope()

double forcemain_getFricSlope	(	int	j,
		double	v,
		double	hrad )

Computes the headloss per unit length used in dynamic wave flow routing for a pressurized force main using either the Hazen-Williams or Darcy-Weisbach flow equations.

Parameters

[in]	j	Link index.
[in]	v	Flow velocity (ft/sec).
[in]	hrad	Hydraulic radius (ft).

Returns

A force main pipe's friction slope.

Note

The pipe's roughness factor was saved in xsect.sBot in conduit_validate() in LINK.C.

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forcemain_getRoughFactor()

double forcemain_getRoughFactor	(	int	j,
		double	lengthFactor )

Computes an adjustment factor for a force main that compensates for any artificial lengthening the pipe may have received.

Parameters

[in]	j	Link index.
[in]	lengthFactor	Factor by which a pipe will be artifically lengthened.

Returns

A roughness adjustment factor for a force main.