Fluid Flow in an Open Channel | Online Calculator

Fluid Dynamic Calculators

Fluid Flow in an Open Channel

In this calculation, an open channel with a depth H, cross-sectional area A, length L and wall roughness Δ is considered. The channel has a height difference Δh along its entire length. A steady flow of fluid with a density ρ and dynamic viscosity μ flows through the channel.

As a result of calculations, the volumetric flow rate Q is found, determined by the following equation:

Q = A*C*(i*R)1/2

C - viscous friction coefficient;
i - relative slope of the channel;
R - channel hydraulic radius.

The flow velocity W, friction coefficient λ and Reynolds number Re are also calculated.

Open channel flow
Open channel flow calculation

INITIAL DATA

L - Channel length;

H - Channel depth;

Δh - Altitude difference between inlet and outlet of the channel (h1 - h2 at the figure);

A - Sectional area of the channel;

ρ - Fluid density;

μ - Dynamic fluid viscosity;

Δ - Absolute roughness of inner sutface of the channel.

RESULTS DATA

W - Average velocity of the flow.

Q - Volumetric flow rate.

Re - Reynolds number.

λ - Viscous friction coefficient.

Channel length (L)

Channel depth (H)

Height difference (Δh)

Sectional area (A)

Fluid density (ρ)

Dynamic viscosity (μ)

Absolute roughness (Δ)

Flow rate (W)

Volumetric flow rate (Q)

Reynolds number (Re)

Friction coefficient (λ)

BASIC FORMULAS

Reynolds number:

Re = W*D*ρ / μ;

Laminar sublayer thickness:

δlam = 68,4*Re-0.875*Dg / 2;

Hydraulic diameter:

Dg = 2A / (A/H + H);

Viscous friction coefficient, depending on absolute roughness Δ:

λ = 0.316*Re-0.25 at δlam > Δ;

λ = 0.11(Δ / Dg + 68 / Re) 0.25 at δlam < Δ;

Volumetric flow rate:

Q = A*(8g*Δh*D/2λ*L)0.5

Average flow velocity:

W = Q / A

INITIAL DATA

L - Channel length;

H - Channel depth;

Δh - Altitude difference between inlet and outlet of the channel (h1 - h2 at the figure);

A - Sectional area of the channel;

ρ - Fluid density;

μ - Dynamic fluid viscosity;

Δ - Absolute roughness of inner sutface of the channel.

RESULTS DATA

W - Average velocity of the flow.

Q - Volumetric flow rate.

Re - Reynolds number.

λ - Viscous friction coefficient.

FLUID PROPERTIES

Fluid

Dynamic viscosity

Pa*s

(lb*s/ft2)

Density

Kg/m3

(lb/ft3)

Water

0.001

(0.0000208)

1005

(62.8)

Freon-11

0.00048

(0.00001)

1494

(93.4)

Freon-12

0.00028

(0.00000586)

1330

(83.1)

Freon-22

0.00025

(0.00000522)

1202

(75.1)

Freon-113

0.00074

(0.0000155)

1573

(98.3)

Kerosene

0.00256

(0.0000535)

804

(50.25)

Benzene

0.00069

(0.0000144)

879

(54.9)

Glycerol

1.393

(0.029)

1261

(78.8)

Ethanol

0.00122

(0.0000255)

789

(49.3)

Mercury

0.00159

(0.0000332)

13545

(846)

Linseed oil

0.044

(0.000919)

924

(57.75)

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