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I read a study done some time after the deaths at a Pearl Jam concert in Roskilde, Denmark. If I recall correctly (I can't seem to find the paper now) they posi

by mstade 7y ago

I read a study done some time after the deaths at a Pearl Jam concert in Roskilde, Denmark. If I recall correctly (I can't seem to find the paper now) they posited that crowds could be simulated by way of particles in a fluid dynamics system, and that a common property of concert accidents such as Roskilde was the lack of pressure release "valves" for lack of a better word. If you only have one exit from the mosh pit, then pressure will mount at that choke point, possibly causing further accidents, and making it harder for emergency services to reach the injured parties. With multiple exits acting as release valves this problem is alleviated, and they used simulations of particles to prove this. Or something like that. Point is, your comment on particle flows dug this reference up from somewhere deep in the back of my mind. It was a really interesting study, I'll try to find a link.

roel_v 7y ago
Yes there is lots of research on this, years ago I was in a project with a group (CASA) at UCL (Leeds) where this is one of their main topics of study - https://www.ucl.ac.uk/bartlett/casa/ https://www.ucl.ac.uk/bartlett/casa/ . If you google e.g. 'agent based simulation pedestrian' you'll find 100's of papers doing this at various scales, as well as dedicated software packages to simulate for studies of shopping mall layout, sports stadium layout etc. Years ago I entertained starting a business in this field - it was essentially exactly what you say, doing analysis for events as part of their risk assessment to see if event locations are safe under various patterns of (aggregate) visitor movement. At the time (15ish years ago?) that wasn't really done for anything but the largest events. The idea never really went anywhere but it's an interesting topic I still think about every now and then.
wincy 7y ago
I've heard they model the crowds for the Hajj in Mecca this way as well.
majewsky 7y ago
> they posited that crowds could be simulated by way of particles in a fluid dynamics system I sometimes have the same thought when traversing a particularly packed mall. Crowds appear to me to be a non-Newtonian fluid, because internal friction increases rapidly under pressure.

by mstade 7y ago

roel_v 7y ago

Yes there is lots of research on this, years ago I was in a project with a group (CASA) at UCL (Leeds) where this is one of their main topics of study - https://www.ucl.ac.uk/bartlett/casa/ https://www.ucl.ac.uk/bartlett/casa/ . If you google e.g. 'agent based simulation pedestrian' you'll find 100's of papers doing this at various scales, as well as dedicated software packages to simulate for studies of shopping mall layout, sports stadium layout etc. Years ago I entertained starting a business in this field - it was essentially exactly what you say, doing analysis for events as part of their risk assessment to see if event locations are safe under various patterns of (aggregate) visitor movement. At the time (15ish years ago?) that wasn't really done for anything but the largest events. The idea never really went anywhere but it's an interesting topic I still think about every now and then.

wincy 7y ago

I've heard they model the crowds for the Hajj in Mecca this way as well.

majewsky 7y ago

> they posited that crowds could be simulated by way of particles in a fluid dynamics system I sometimes have the same thought when traversing a particularly packed mall. Crowds appear to me to be a non-Newtonian fluid, because internal friction increases rapidly under pressure.