# Richard Smith's blog

## Stonehenge Vortex Revealed by CFD

Forget all the speculation as to the purpose of Stonehenge. After a detailed Computational Fluid Dynamics (CFD) study it appears Stonehenge's original purpose was to generate a focused vortex.

CFD Simulation of a Vortex at StonehengeStreamline arrows colored by velocity

## Bicycle Wheel and Fender Aerodynamics

In the bicycle world aerodynamics has taken on an ever increasingly important role. Cyclists are willing to go to great lengths and expense to realize performance enhancements through optimized aerodynamics in bicycle frames, wheels, and components. I thought it would be interesting to see where in the spectrum of aerodynamics performance disc rotors and fenders (mud guards) lie using Computational Fluid Dynamics (CFD) as our guide.

CFD Simulation of a Wheel with a Fender and Disc RotorVelocity contours at 25 degree yaw angle

## Speedy Downhill

If you want to go fast downhill then you better know your aerodynamics. For an alpine skier and a downhill cyclist, drag is the force holding them back, but with the application of some basic fluid dynamics knowledge they can go faster - a lot faster.

Eric Barone - 223,30 km/h (138.752 mph) - World mountain bike speed record

## Plasma-Powered Drag Reduction for Trucks

What if you could reduce the drag of a tractor-trailer truck by 23% and therefore reduce fuel consumption by 11%? Further, what if the only modification to the trailer was to apply some decals and hook up an electric power source? According to Plasma Stream Technologies these savings are viable if the plasma flow control they are developing fulfills its promise.

Improve the Pressure Recovery Behind a Trailer using PlasmaGeometry courtesy of Nectar Design

## Rise and Fall of Winglets in MotoGP

MotoGP is the pinnacle of motorcycle racing, just like Formula 1 is to car racing, so it should come as no surprise that aerodynamics is a key element for success. The focus in MotoGP was on drag reduction through streamlined fairings, helmets, and outfits. Then in 2015 Ducati added winglets to their front fairings to produce downforce.

Winglets Come and Go in MotoGP

## Fluid Dynamics in 2016

In our third and final review post for 2016, catch up on general fluid dynamics topics that will ensure your future is so bright you'll have to wear shades in 2017.

McLaren 2010 MP4-25: F-duct carLicense: CC BY 2.0, Andrew Griffith

## Lessons in CFD from 2016

In our second review post for 2016, here are lessons and guidance to make your Computational Fluid Dynamics (CFD) more productive in 2017. "Those who do not learn [from] history are doomed to repeat it."

CFD Simulation Results Revealed by Transparency

## CFD Simulations of 2016

As 2016 draws to a close it is review time. Here are the Computational Fluid Dynamics (CFD) simulations that made 2016 so colorful, just in case you missed them the first time around.

CFD Simulation of Air Speed Surface Contours