Ultrasonic Doppler Flow Meter

Reference data and engineering information about ultrasonic doppler flow meter for fluid mechanics applications.

Overview

Engineering reference data for Ultrasonic Doppler Flow Meter in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Symbol	Description	Unit
$Re$	Reynolds number	—
$\rho$	Fluid density	kg/m³
$v$	Flow velocity	m/s
$D$	Characteristic dimension	m
$\mu$	Dynamic viscosity	Pa·s
$P$	Pressure	Pa
$f$	Darcy friction factor	—

Operates by measuring the frequency shift of ultrasonic waves reflected from particles or bubbles suspended in the fluid. The velocity is derived from the Doppler shift formula, making it suitable for dirty or aerated liquids but dependent on the presence of reflectors.

Time of Flight (Transit Time) Ultrasonic Flow Meter

Measures the difference in travel time of ultrasonic pulses sent upstream and downstream between two transducers. This method does not rely on suspended particles and is suitable for clean liquids.