THE AIR FLOW AROUND A CLOTHED CYLINDER

PART 1. AN EXPERIMENT ON THE OUTER FLOW FIELD

Abstract

An experiment was conducted for revealing the aerodynamic characteristics of cylinders clothed with fabrics. Pressure distributions on the outer and inner surfaces of cylinders and velocity distributions around these cylinders were measured. The results showed that the outer pressure distributions on the cylinders clothed with different fabrics were identical, but that they were different from that on a naked cylinder. This is because the air flow around the clothed cylinder separates from the surface earlier than that around the naked one. The inner pressure distribution were strongly affected by the fabrics of low permeability, but they were scarcely influenced in the case of high permeability. Measured velocity distributions indicated the forward shift of the separation point and they were found to be influenced seriously by the fabrics of high permeability; the boundary layer on the outer surface became thick and the turbulence level in the layer was high. In the case of low permeability, however, the velocity distribution was hardly influenced by clothing except the shift of the separation point.