Effects of a Turbulent Free Stream and a Wall Roughness on the Flow Normal to a Cylinder at Subcritical Reynold's Numbers.
Abstract
The flow normal to a circular cylinder at subcritical Reynold's Numbers was investigated to determine the feasibility of using subcritical Reynold's Number model tests to determine supercritical behavior. This finds application in the area of predicting wind loads on structures with circular cross-sections such as chimneys and cooling towers. The measurements were made in the VKI's L2A low speed wind tunnel. The measurements include static pressure, r.m.s. pressure fluctuation, wall shear stress, and velocity profiles at 90 deg. The r.m.s. pressure fluctuations were measured with a flush mounted Kulite probe. The wall shear stress was measured by a flush mounted hot film probe. The velocity profiles were measured with a wire anemometer. Also velocity measurements were made at 1/2mm, 1mm, and 2mm from the surface of the cylinder with flush mounted hot wires. The cylinder was rotated to generate the velocity at a fixed height from the cylinder as a function of the angle to the freestream. The smooth cylinder in the quiet freestream exhibited behavior consistent with the data found in the literature. Both the smooth cylinder in the turbulent freestream and the rough cylinder in the quiet freestream showd some of the characteristics of a cylinder at supercritical Reynold's Numbers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1978
- Accession Number
- ADA069112
Entities
People
- D. Olivari
- Mark Moeller
Organizations
- von Kármán Institute for Fluid Dynamics