Photo Contest
2013 Photo Contest -Beautiful Flames- The HIGHEST AWARD
“Spiral” tubular flame formed by a rapidly mixed type ~Ice-cream-like Flame~
AWATA Hirotaka, ASANO Yuuya, HAYASHI Jun, AKAMATSU Fumiteru
Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871, Japan
Explanation
This flame was formed by rapidly mixing type of tubular flame burner. Although it looks like a cylindrical flame with the long exposure observation, a symmetric spiral striped pattern was observed inside of the cylindrical glass combustion tube with a short exposure photograph. This fantastic spiral striped pattern can be seen in the cylindrical glass combustion tube as well as outside of the combustion tube. The high brightness spiral strip appeared in the cylindrical glass combustion tube looks like a waffle cone, and the low brightness spiral sprit appeared outside of the combustion tube looks like an ice cream. This photograph captured an instantaneous beautiful feature of the rapidly mixing type tubular flame.
Camera & Lens: NIKON D7000 & Nikon AF24 F2.8D
F-number: F2.8, Shutter speed: 1/640 s, ISO:6400
2013 Photo Contest -Beautiful Flames- The MERIT AWARD (in Japanese)
「巨大カリフラワー火炎」
金 佑勁1，茂木 俊夫1，桑名 一徳2，土橋 律1
1 東京大学 大学院工学系研究科
2 山形大学大学院理工学研究科
作品の解説
この写真は，一辺が3mの立方体型ステンレス枠(体積V=27m3)に薄いビニルシートを張り付けて形成した空間内にプロパン/空気の混合気当量比φ=0.8を貯留し，伝ぱする火炎を高速度カメラにより測定したものである．大規模での可燃性ガス/空気混合気の球状伝ぱ火炎では，火炎の不安定性により火炎の乱れが生じ，自発的に加速する．特に，火炎のスケールが大きくなると流体力学的不安定性により火炎が乱れ，そのときの火炎面は自己相似的なフラクタル構造を有することが示唆されたので，この写真を「巨大カリフラワー火炎」と名付けた．