# World Cup: Simulating Stadium Foot Traffic in SOLIDWORKS

Have you ever watched a large group of people on the move? From on high you can see the people moving around obstacles, creating pools of stationary traffic and choke points where the traffic slows to a crawl before accelerating on. It’s just like seeing streamline in the flow of a gas or a fluid, but with people. Flow simulation assumes continuum mechanics which is a good analogy for when a group of people are tightly contained and they are all moving towards an exit. So that got me thinking: can you model the movement of people with SOLIDWORKS Flow Simulation? What large group of people on the move should I look at?

Right now the sporting world is looking towards Brazil and the 2014 FIFA World Cup. Over 30 days, 31 national teams will play a total of 64 games in 12 stadiums in front of 100,000’s of people, with millions watching on television, to find the best football (soccer) nation in the world.

That’s a lot of people to get in and out of a stadium and it seemed like a nice proving ground for my ‘human flow test’.  The first step is to create a simple stadium layout (see below). For this proof of concept I modeled a corner section of one seating level, ignoring the sloping nature of the stands but including individual seats, people entering from a higher level, trash cans, concession stands and multiple exits.

So we have our stadium, but how do we model the people moving? For this simple proof of concept test, I decided to have the seats fully occupied (it is the World Cup after all) and apply a mass flow to each seat. This in effect is modelling that as soon as one person gets up another immediately appears and gets up as well. In essence, it is an ‘infinite human flow’ simulation, but this simple assessment will allow us to evaluate the ‘choke’ points in the flow where the mass of people is such that the crowd would naturally slow down.

The first set of results, below, shows the velocity of our ‘infinite human flow’ and the interpretation is different than normal. For simplicity, I defined an incompressible flow in SOLIDWORKS Flow Simulation which means that the fluid has to go faster (the red areas) to get out of the stadium due to the constant flow from the seats creating an increasing pressure. However, real people act differently than my ideal fluid. We should read this result to show the red areas as regions of were the crowd is under pressure from the mass of people trying to get through a smaller region. In the real world, these red regions are where the movement of people will slow down.

Flow streamlines are a good way to view where the crowd leaves to exit. The results below show that the movement of the crowd is hindered by the people leaving the stairs.

So we need to adjust the floor plan to balance the flow. At the same time, I increased the size of the model to over 6000 seats and I have moved the trash cans to smooth out the flow.

The new set of results looks very promising. The areas of ‘pressure’ build up around the exits has not grown significantly, but we are seeing movement from the front of the seating block, where the crowd appears to be flowing smoothly.

So that’s how you can get out of the stadium, but getting out of the car park, now that’s a different matter.

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#### Stephen Endersby

Product Manager at SolidWorks