Heat Transfer on Cylinder Covered with Close-fitting Fabrics : part I, Wind Penetration through Fabrics

抄録

The phenomena of air penetration into the fabric coverings over a cylinder placed in a uniform cross flow have been examined theoretically and experimentally. It is found that the air penetrating from upstream side of fabric mostly flows downstream through a thin layer between the fabric and the cylinder, which is called a 'contact layer'. This thin contact layer is more permeable than the bulk of fabric because of the surface fuzz. The fluid-dynamical property of this layer is described by a characteristic number α^*, which is determined for each condition of fitting the material for the cylinder : 0.75 for the felt close around the cylinder, 0.25 for the felt stuck with adhesive tape, and 0.0 for the elastic bandage stuck with paste. The penetration flow is shown to be a function of α^*, dynamic pressure of incident flow, and intrinsic properties of the material (thickness and permeability).