Pi is a truly remarkable number – it even has its own special day, the 14th March (3.14 in American date notation). This year to celebrate Pi day we are highlighting the importance of Pi in the world of Engineering.
1. Space Engineering
Space Engineers use Pi all the time. From getting a Space craft into the correct orbit, to calculating the size of a landing Parachute, Pi is fundamental to the calculations made in the Space Sector.
Further Reading: 18 Ways that NASA uses Pi
2. Construction and Civil Engineering
There are a surprising number of Circular Buildings which require Pi in their initial design and construction. One of the most famous examples in the UK is the doughnut shaped headquarters of GCHQ in Cheltenham.
Engineers will also need Pi while using the Euler Buckling Formula which prevents supporting columns from buckling and collapsing.
Euler Buckling Formula
![\[ F=\frac{n \pi^2 E I}{L^2}\]](https://www.mathscareers.org.uk/wp-content/ql-cache/quicklatex.com-5355f2d4012b3609239a903279b1d7fc_l3.svg "Rendered by QuickLaTeX.com")
[Where F = allowable load, n = factor accounting for the end conditions, E = modulus of elasticity, L = length of column, I = Moment of inertia.]
3. Product Design
Lots of products are round or have round components. From Baked Bean tins to Ball Bearings, Product Design engineers use Pi to design and manufacture the round objects we need and use all the time.
4. Aeronautical Engineering
Pi plays a big role in modelling flow of air around aircraft. One example is in the calculation of ‘Induced Drag’ 
![\[ D_i=\frac{L^2}{0.5 \rho_0^2 V_E^2 \pi b^2}\]](https://www.mathscareers.org.uk/wp-content/ql-cache/quicklatex.com-940df128feb7ee56b93693e5e6ed5fa7_l3.svg "Rendered by QuickLaTeX.com")
[L is the Lift 
is the standard density of air at sea level, 
is the equivalent airspeed, b is the wingspan.]
5. Control Engineering
Control Engineers use Pendulums to detect tiny vibrations while protecting vital systems such as reservoir dams. The formula for the Period of a Simple Pendulum includes Pi.
![\[ T=2 \pi \sqrt{\frac{L}{g}}\]](https://www.mathscareers.org.uk/wp-content/ql-cache/quicklatex.com-22c37647dd91b7e3bf2242604bb46344_l3.svg "Rendered by QuickLaTeX.com")
[T:Period; L:Pendulum Length; g:Acceleration due to Gravity]
6. Pipeline Engineering
Engineers use Pi in the Hagen–Poiseuille equation, calculating the Pressure Difference between the two ends of a pipe.
![\[ \Delta P=\frac{8 \mu L Q}{\pi R^4}\]](https://www.mathscareers.org.uk/wp-content/ql-cache/quicklatex.com-308c3d5a9a131027de5b1209ba00c8b9_l3.svg "Rendered by QuickLaTeX.com")
[
: Pressure difference between the two ends of the pipe; 
Dynamic viscosity; L: Length of the pipe; Q: Volumetric Flow Rate; R: Pipe Radius]
7. Rollercoasters
Next time you are enjoying a visit to a theme park, take a moment to appreciate the Engineers who have used Pi to calculate the Angular Velocity of your ride.
8. Chemical Engineering
Chemical Engineers try to choose the strongest and most efficient shapes to store liquids and gases. While a sphere might be the strongest shape, spherical pressure vessels can be expensive to produce and are reserved for high pressure fluids that need the most protection. Chemical Engineers use Pi to develop alternative storage solutions such as cylinders with elliptical heads.
9. Mechanical Engineering
The invention of the wheel is one of humanity’s greatest achievements, allowing us to travel from A to B with ever increasing ease. Mechanical engineers use Pi to calculate the circumference of these wheels with accuracy.
10. Sports Engineering
From tennis balls to cycling tracks, there are lots of round things in the world of Sport, meaning that Pi is essential to the work of a Sports Engineer. Find out more about Sports Engineering as career in this video from the Sports Engineering Research Group (SERG) at Sheffield Hallam University.
An Introduction to Sports Engineering Video
Image Credits
Photo by Taso Katsionis on Unsplash
Photo by NASA on Unsplash
Photo by Random Thinking on Unsplash
Photo by NOAA on Unsplash
Photo by Prateek Srivastava on Unsplash
Photo by Mike Benna on Unsplash
Photo by Itai Aarons on Unsplash
Tank image CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1435934
Photo by Freddy G on Unsplash
