pressflow_depth_sub: Backwater Height Upstream A Inlet Under Pressure (Bernoulli)

In hydReng: Hydraulic Engineering Tools

Backwater Height Upstream A Inlet Under Pressure (Bernoulli)

Description

Calculates the backwater height upstream of an inlet (pipe or rectangle) under pressure (Bernoulli). The outlet is submerged; hence, an exit loss (xi_a) has to be specified.

Usage

pressflow_depth_sub(
  z0, z1, Q, h1, v1, Di = NULL, h = NULL, b = NULL, L, ks = NULL, kst, xi_a,
  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].
Q	Flow [m^3/s].
h1	Water depth downstream the outlet [m].
v1	Velocity downstream the outlet [m/s].
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_a	Exit loss, according to Borda-Carnot formula (1 - A1/A2)^2 [-].
xi_e	Entrance loss [-]. Default = 0.5.
nu	Kinematic viscosity [m^2/s]. Default = 1.14e-6.
calc_lam	Defines if lambda should be calculated with ks or kst.

Value

Returns the backwater height upstream the inlet:

h0

Water depth upstream the inlet [m].

v

Flow velocity [m/s].

Examples

# Flow in a pipe under pressure with ks value
pressflow_depth_sub(z0=415,z1=413,Q=5.18,h1=2,v1=4,L=20,Di=1,ks=0.01,
calc_lam="ks",xi_a=0.5)

# Flow in a rectangle under pressure with kst value
pressflow_depth_sub(z0=415,z1=413,Q=13.7,h1=2,v1=4,L=20,b=2,h=1,kst=60,
calc_lam="kst",xi_a=0.5)

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