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Journal of Flow Visualization and Image Processing
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN Print: 1065-3090
ISSN Online: 1940-4336

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.v7.i1.70
10 pages


Shigeaki Inada
Department of Mechanical System Engineering, Gunma University, 1-5-1 Tenjincho, Kiryu, 376-8515, Japan
Masahiro Yamazaki
Department of Mechanical System Engineering, Gunma University, 1-5-1, Tenjincho, Kiryu, Gunma 376-8515 Japan


The natural convective thermal field in the air around a horizontal isothermal cylinder with a longitudinal plate fin is visualized by means of laser holographic interferometry. The cylinder is either heated or cooled to maintain a constant surface temperature, while either a copper (conducting) or a balsa (insulating) fin is attached longitudinally on the cylinder at various circumferential locations to grasp the effect of fin-air interaction on convective flow patterns that appear in the form of interference fringes. As a result, a vertically ascending (in the heated cylinder case) or descending (cooled case) plume interacts with an air stream along the fin. Subsequently, it is discovered that an optimal circumferential fin location exists at which local heat transfer performance around the cylinder becomes uniform. The optimal circumferential location is unaffected by fin material and is unchanged, always situated downstream of the plume irrespective of the cylinder being heated or cooled. An additional experiment is performed on frost formation on a cooled cylinder. It is found that a substantially more uniform thickness of frost is formed on the cylinder surface when a fin is attached on the optimal circumferential location than in the absence of a fin.