Impact of scaling and body movement on contaminant transport in airliner cabins

Studies of contaminant transport have been conducted using small-scale models. This investigation used validated Computational Fluid Dynamics (CFD) to examine if a small-scale water model could reveal the same contaminant transport characteristics as a full-scale airliner cabin. But due to similarity problems and the difficulty of scaling the geometry, a perfect scale up from a small water model to an actual air model was found to be impossible. The study also found that the seats and passengers tended to obstruct the lateral transport of the contaminants and confine their spread to the aisle of the cabin. The movement of a crew member or a passenger could carry a contaminant in its wake to as many rows as the crew member or passenger passed. This could be the reason why a SARS infected passenger could infect fellow passengers who were seated seven rows away. To accurately simulate the contaminant transport, the shape of the moving body should be a human-like model.

► The small-scale water model did not work in the same way as the full-scale air model.
► CFD models have no scaling issues.
► A walking person can carry a contaminant from its source to very far away.
► The body movement could cause transmission of the SARS pathogen from the infected passenger to those seated far away in Flight 112 in 2003.