Reynolds number calculator

laminar or turbulent flow

online since 2001

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Action
Calculation setup
Flow rates and velocity
Reynolds number
Pipe dimensions
Fluid properties

Calculator description

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Also, read about calculation procedures, what you have to know for the calculations and what limitations apply.

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issues and answers

Description

q - volumetric flow rate
Fluid flow rate in terms of units of volume per unit of time
ṁ - mass flow rate
Fluid flow rate in terms of units of mass per unit of time
V - velocity
Flow velocity in terms of units of distance per unit of time
D - pipe diameter
Internal circular pipe diameter
H - channel height
The height of channel for rectangle shaped pipe
W - channel width
The width of channel for rectangle shape pipe
A - area
Internal pipe cross section area
ρ - fluid density
Mass per unit of volume
T - temperature
Fluid temperature for gas density calculation based on the ideal gas state equation
p - pressure
Fluid pressure at the start of the pipe for gas density calculation based on the ideal gas state equation
R - gas constant
Gas constant in terms of energy per unit of mass and temperature, for gas density calculation using ideal gas state equation
ν - kinematic viscosity
Result of fluid particles colliding to each other and moving at different velocities in terms of area per square unit of time
μ - dynamic viscosity
Result of fluid particles colliding to each other and moving at different velocities in terms of mass per square unit of distance and time
Re - Reynolds number
Dimensionless number representing viscous versus inertial forces ratio

Calculation setup

Select value to input. You should enter selected one. The other two will be calculated
q
volumetric flow rate
mass flow rate
V
flow velocity
Select value to input. You should enter selected one. The other one will be calculated. Available only if the gas is selected fluid
ρ
fluid density
T
temperature
Select value to input. You should enter selected one. The other one will be calculated
ν
kinematic viscosity
μ
dynamic viscosity
Select fluid type
liquid
for incompressible fluids
gas
for fluids where ideal gas state equation is used. Enables selection between density and temperature to input.
Select pipe shape
round pipe
full cross section fluid flow
rectangle pipe
for rectangle channels and full cross section flow

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