Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

Dynamic Pressure

Dynamic pressure is the kinetic energy per unit volume of a fluid in movement.

Dynamic pressure is the kinetic energy of a flowing fluid - liquid or gas - per unit volume - and can be expressed as

p d = 1/2 ρ v2(1)

where

p d = dynamic pressure (N/m2(Pa), lb f /ft2(psf))

ρ = density of fluid (kg/m3 , slugs /ft3 )

v = velocity (m/s, ft/s)

Dynamic Pressure Calculator - SI Units

The default values below are for water with density of 1000 kg/m3 .

  • 1 N/m2= 1 Pa = 1.4504x10-4 lb f /in2(psi) = 0.02089 lb f /ft2(psf) = 1x10 -5 bar = 4.03x10-3 in water = 0.336x10-3 ft water = 0.1024 mm water = 0.295x10-3 in mercury = 7.55x10-3 mm mercury = 0.1024 kp/m2= 0.993x10 -5 atm

Dynamic Pressure Calculator - Imperial Units

The default values below are for water with density of 1.940 slugs .

Some common densities at atmospheric pressure:

  • Water - 0 oC - 1000 kg/m3
  • Water - 32 o F - 1.940 slugs/ft3
  • Air - 20 oC - 1.2 kg/m3
  • Air - 60 o F - 2.373 10-3 slugs/ft3

Example - The Dynamic Pressure in a Water Flow

The dynamic pressure in water with - temperature 20 oC - density 1000 kg/m3 and velocity 5 m/s - can be calculated as

p d = 1/2 (1000 kg/m3 ) (5 m/s)2

= 12500 Pa

= 12.5 kPa

Example - Hurricane and Force acting on a Wall

The dynamic pressure in a hurricane with air temperature 20 oC, density of air 1.2 kg/m3 and wind speed 37 m/s can be calculated as

p d = 1/2 (1.2 kg/m3 ) (37 m/s)2

= 821 Pa (N/m2)

The force acting directly on a wall with area 10 m2 can be calculated as

F = p d A

= (821 N/m2) (10 m2)

= 8210 N

= 8.2 kN

- almost the weight of a small car.

Note! - the real force acting on the wall - or an other obstruction in the wind - is in general more complicated to calculate due to drag , turbulence and other effects.

wind velocity and wind load on a surface

Related Topics

  • Fluid Mechanics

    The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.

Related Documents

Search

Search is the most efficient way to navigate the Engineering ToolBox.

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse !

Translate this Page

Translate this page to Your Own Language .

About the Engineering ToolBox!

Privacy Policy

We don't collect information from our users. More about

We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy here.

You can change your privacy settings by clicking the following button: .

Citation

This page can be cited as

  • The Engineering ToolBox (2008). Dynamic Pressure. [online] Available at: https://www.engineeringtoolbox.com/dynamic-pressure-d_1037.html [Accessed Day Month Year].

Modify the access date according your visit.

3D Engineering ToolBox - draw and model technical applications! 2D Engineering ToolBox - create and share online diagram drawing templates! Engineering ToolBox Apps - mobile online and offline engineering applications!

Unit Converter

















































3.27.8

.