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# Hydraulic Diameter of a Rectangular Duct (fully filled)

AndrewS.Hydraulic Diameter of a Rectangular Duct (fully filled)

The **Hydraulic Diameter of a fully filled Rectangular Duct** calculator compute the hydraulic diameter of a fully filled rectangular duct based on its dimensions.

**INSTRUCTIONS:** Choose units and enter the following:

- (
**a**) This is the width of the rectangular duct. - (
**b**) This is the height of the rectangular duct.

**Hydraulic Diameter (D _{H}):** The calculator returns the diameter in meters. However, this can be automatically converted to compatible units via the pull-down menu.

#### The Math / Science

The formula for the Hydraulic Diameter of a Rectangular Duct (fully filled) is:

`D_H = (4*a*b)/(2*(a+b))`

where:

- D
_{H}is the hydraulic diameter of a fully filled rectangular duct . - a is the width of the duct.
- b is the height of the duct.

A hydraulic diameter is useful for dimensionless quantities (e.g. Reynolds number) which employ a single variable for flow analysis.

Hydraulic diameter is mainly used for calculations involving turbulent flow. Secondary flows can be observed in non-circular ducts as a result of turbulent shear stress in the turbulent flow. Hydraulic diameter is also used in calculation of heat transfer in internal-flow problems.

**Hydraulic Diameter of a Rectangular Duct (fully filled)**, is used in 1 calculator.

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