自由空気中に拡散する水平ガス棒中の火炎伝播
燃焼現象としての“ひとだま”
1966 年 14 巻 149 号 p. 170-176
詳細
1966 年 14 巻 149 号 p. 170-176
The phenomenon of "Hitodama", a fairly popular term from ancient in Japan and probably corresponding to will-o'-the-wisp, is studied from the viewpoint of combustion of gases. The viewpoint has come out of the examination on nearly 100 actual examples mostly observed by the acquaintances of the author. An experimental simulation is tried in a wind-tunnel, in which the setup is so devised that the mixing of methane and surrounding air is caused merely by interdiffusion. A long, horizontal column of methaneair mixture thus formed is ignited to establish a propagating flame. The observed flames take three representative types; long one with a ringshaped head, one with a conically-grooved head, and spherical one with a short tail, according to the concentration profile in the column. The analytical investigation gives calculated shapes of methane flames which are in a fairly good agreement with observed ones.
