For Santa to meet his aggressive toy delivery schedule on Xmas eve it would appear that he has to travel impossibly fast. Yet there are often sightings of Santa on his rounds, which seems to contradict this high speed hypothesis. The only way to explain Santa's whereabouts is that he uses a Reality Distortion Field (RDF). Santa's special projects division (known as Elf Works) is responsible for the RDF and it remains tight lipped on how it works. However, with the help of Computational Fluid Dynamics (CFD) we have pieced together how the RDF might work.

CFD Simulation of Reality Distortion Field Bubble Around Santa and his EntourageIso-surfaces of velocity magnitude

### The Reality Distortion Field Hypothesis

Snippets of information have leaked out about the RDF, and from these snippets we've been able to splice together a better picture of how it might work. Santa, his sled, and his reindeer traverse space within a bubble. The bubble proceeds at the relative sedate speed of 10 m/s, directly compatible with the speed reindeer can comfortable maintain. This relatively slow speed is why there are mass sightings of Santa on his rounds.

The magic of the RDF is that it distorts the observer's reality (i.e, our reality) by scaling up quantum effects usually reserved for extremely small particles. At the instant an observer needs to perceive Santa, the RDF ensures a perfect copy of Santa is initiated and does the Santa dance, i.e., lands, delivers presents, and eats cake. This effect has been found to be inversely proportional to the observer's age, which is why children are more susceptible to Santa. The appearance of Santa is analogous to a computer game that only initiates objects in the immediate vicinity of the player to save resources and then when the player moves on the instance  vanishes. At first we thought that Rudolf's red nose played an important role in the RDF, but it turns out that was a red herring to put us off the scent.

### CFD

So how can CFD help? For the first time we have been able to determine the exact size of the RDF bubble and have simulated the relatively slow air flow around it using an accurate laser scan of Santa and his entourage from the SketchUp 3D warehouse.

### Model

Model of Reality Distortion Field Bubble Around Santa and his Entourage

### Results

CFD Simulation of Reality Distortion Field Bubble Around Santa and his EntourageIso-surfaces of velocity magnitude

CFD Simulation of Reality Distortion Field Bubble Around Santa and his EntourageVelocity Arrows

### Notes

• Simulation background image credit: Orion Nebula, Chandra X-Ray Observatory
• SketchUp geometry credit: Santa's 2007 Sleigh, Oz the Wiz
• CFD Simulation was set up and performed in Caedium Professional using the incompressible, steady-state RANS solver, and the k-omega SST turbulence model