Enter the flow through the orifice and the orifice area into the calculator to determine the orifice velocity.

Orifice Velocity Formula

The following equation is used to calculate the Orifice Velocity.

VO = OF / OA
  • Where VO is the orifice velocity (m/s)
  • OF is the orifice flow rate (m^3/s)
  • OA is the orifice area (m^2)

To calculate the orifice velocity, divide the orifice flow rate by the orifice cross-sectional area.

What is an Orifice Velocity?


An orifice velocity is a measure of the velocity of fluid moving through an orifice.

How to Calculate Orifice Velocity?

Example Problem:

The following example outlines the steps and information needed to calculate Orifice Velocity.

First, determine the orifice area. In this example, the orifice area is found to be 2 m^2.

Next, determine the orifice flow rate. In this case, the orifice flow rate is measured to be 50 m^3/s.

Finally, calculate the Orifice Velocity using the formula above:

VO = OF / OA

VO = 50 / 2

VO = 25 m/s


What factors can affect orifice velocity?

Several factors can influence orifice velocity, including the viscosity and density of the fluid, the temperature and pressure conditions, and the shape and roughness of the orifice. Changes in these factors can lead to variations in the flow rate and subsequently alter the velocity of the fluid passing through the orifice.

How does the size of the orifice impact the velocity?

The size of the orifice, specifically its cross-sectional area, directly impacts the velocity of the fluid passing through it. According to the orifice velocity formula (VO = OF / OA), a smaller orifice area (OA) will result in a higher velocity (VO) for a given flow rate (OF), and vice versa. This is because the fluid is forced to accelerate to pass through the smaller opening.

Can orifice velocity be used to measure flow rate?

Yes, orifice velocity can be used as a means to measure flow rate. By knowing the velocity of the fluid passing through an orifice and the cross-sectional area of the orifice, the flow rate can be calculated. This principle is commonly applied in various types of flow meters, where the flow rate is deduced from the measured velocity and the known area of the orifice.