Experiments and Analysis of Interaction Among Multiple Fires in Equidistant Fire Arrays

The study of dynamics of multiple fires is important to gain a physical insight of the conditions under which destructive phenomena could result in city fires such those caused by earthquakes. Particularly, heavy populated cities such as Tokyo are highly vulnerable. Unfortunately, previous studies on multiple fires and their dynamics are rather limited. An extensive experimental study has been carried out to examine the fire interactions among freestanding equidistant multiple fires in square arrays, to supplement the authors’ previous related studies. Four square arrays, namely, 5×5, 9×9, 15×15 and 17×17, with various inter-fuel pan distances were treated. The burnout time (BOT) from ignition at every fire in the array was experimentally recorded and expressed as multiples of the BOT of a single free-standing fire as a reference. Since the BOT at any fire location in an array is inversely proportional to an average burning rate (BR) at that location, the local BR can then be directly inferred, and their comparisons thus indications of the physical interactions as affected by the fire location, inter-fuel pan distance and size of the fire array. It is shown that all these parameters play remarkable roles in the interactions among multiple fires in square fire arrays.