pressflow: Flow Under Pressure (Bernoulli)

In hydReng: Hydraulic Engineering Tools

Flow Under Pressure (Bernoulli)

Description

Calculates the flow in a pipe or a rectangle under pressure (Bernoulli). The outlet is not submerged, e.g., the exit loss equals 0.

Usage

pressflow(z0, z1, h0, Di=NULL, h = NULL, b = NULL, L, ks=NULL, kst,
  xi_e = 0.5, nu = 1.14e-6, calc_lam = "kst")

Arguments

z0	Absolute height of upper gate – upstream of the inlet [m.a.s.l].
z1	Absolute height of the pipe/rectangle vertical middle axis at lower gate [m.a.s.l].
h0	Water depth upstream of the gate – upstream of the inlet [m].
Di	Diameter of pipe [m]. If Di is specified, h and b must be NULL.
h	Height of rectangle [m]. If h is specified, Di must be NULL.
b	Width of rectangle [m]. If b is specified, Di must be NULL.
L	Length of pipe [m].
ks	Equivalent sand roughness [m].
kst	Roughness [m^(1/3)/s].
xi_e	Entrance loss [-]. Default = 0.5.
nu	Kinematic viscosity [m2/s]. Default = 1.14e-6.
calc_lam	Defines if lambda should be calculated with ks or kst.

Value

Pressflow returns the flow under pressure:

Q

Discharge [m^3/s].

v

Flow velocity [m/s].

Examples

# Calculate flow in a pipe under pressure with ks value
pressflow(z0 = 415, z1 = 413, h0 = 3, L = 20, Di = 1, ks = 0.01,
  calc_lam = "ks")

# Calculate flow in rectangle under pressure with kst value
pressflow(z0 = 415, z1 = 413, h0 = 3, L = 20, b = 2, h = 1, kst = 60,
  calc_lam = "kst")

hydReng documentation built on April 4, 2025, 1:57 a.m.