Modeling vortex structures control at streamlining of high-rise buildings in the coastal area “sea – land”

Abstract

The motivation of this joint complex studies is related to the actual necessity of analyzing the strong wind impact in the coastline of the “sea-land” typical for Taiwan Island, as well as due to the long-established creative collaboration between partners from the Khristianovich Institute of Theoretical and Applied Mechanics SB RAS and National Cheng Kung University in Taiwan. Experimental studies were carried out in wind tunnels in Novosibirsk and Taiwan, in particular, in November this year, planned further experiments in wind tunnels in Taiwan. Numerical studies were carried out mainly in St. Petersburg, where for more than twenty years the package VP2/3 (velocity-pressure, 2D/3D) has been developing. Interest to the flow past a semicircular cylinder is high due to its phenomenal characteristics: ultra-low negative lift at zero angle of attack. In this paper, this effect is explained numerically, and this body is recommended for testing methods, models and packages. The influence of the Mach number on the flow past a semicircular cylinder at zero angle of attack is illustrated in the Mach number range M = 0 - 0.5. Turbulent regime with a throttling effect gave an exceptional result - the stabilization of the flow in the wake behind the circular cylinder when air is gone through the outlet channel from the zone of increased pressure in front of the body with the release of the jet inside the near wake. There is made a comparison of the experimental behavior of the resistance of a circular cylinder with an increase in the Reynolds number and the calculated dependence for a cylinder in a casing with holes. A three-fold decrease in drag on high Re numbers was detected. Completion of the test section of the T-325M wind tunnel of ITAM SB RAS allowed to increase (in several times) the Reynolds number of an incompressible flow. Design and manufacturing of circular and semicircular cylinders having the structured surface has been performed, for which some preliminary physical experiments in the test section of T-325M wind tunnel of ITAM SB RAS within the Reynolds and Mach numbers range citied above were carried out.