Research Of Reynolds Number Effect On Single-cylindrical Wind Load

Comparing to the rectangular cross-section structures in the flow field, flow characteristics and mechanical properties of cylindrical structure are more sensitive to the change of Reynolds number. In order to simulate the actual flow characteristics of the cylindrical structures that under the low speed wind tunnel, it is needed to reduce the critical Reynolds number, to improve the effective Reynolds number, so that cylindrical model in the low speed wind tunnel could be in the actual high critical region. In this paper, through combining with theoretical research and actual wind tunnel experiment, adding stickers of the the cylindrical surface, grilles in the wind tunnel,the roughness on the surface of the cylinder, the turbulence intensity of flow field are both changed. In order to effectively simulate the actual flow around and mechanical characteristics,the influence of roughness and turbulence intensity to the effective Reynolds number of single-cylindrical structure could be analyzed, in combination with the measurement of pressure distribution on the surface of a cylinder and the calculation of drag coefficient.Through the discussion in uniform flow and two different turbulence degrees and the pressure measure of the smooth cylindrical surface,four different rough surface of cylindrical surface, the cylindrical surface pressure coefficient distribution and the drag coefficient could be got. So the actual flow field characteristics of cylindrical structures and the relationship between the effective Reynolds number and Reynolds number could be comparatively analyzed.In low speed wind tunnel, the measures to simulate the characteristics of actual flow around cylinder could be analyzed.Through summarizing the calculation of theoretical knowledge and analyzing the experimental data,the influence of the flow field in the turbulence intensity, and surface roughness to the pressure coefficient distribution on the surface of a cylinder, the size of the resistance coefficient as well as the changing rule of the cylindrical flow characteristics could be got.Through the analysis of the above rules and the calculation of the experimental data, under various experimental conditions, the feasibility to simulate supercritical flow could be obtained and under the low speed wind tunnel,while simulating cylindrical supercritical flow, corresponding to the minimum nominal Reynolds number and the specific test measures are presented.