AbstractsEngineering

Characteristics of the reverse flow region of a bluff body are newlineclosely related to its geometrical shape. In particular, shape and size of the newlinereverse flow region, location of center of primary vortex, front and rear newlinestagnation points are dependent on the geometrical shape of the bluff body. newlineNumber of researchers has studied the aerodynamic characteristics of newlinerecirculation zone of two dimensional bluff bodies like cylinder of circular, newlinesquare, rectangular and triangular cross section. But limited work was carried newlineout with three dimensional bodies like cone of circular cross section as the newlinebluff body. In the present investigations, cold flow experiments were newlineconducted to study wake axis parameters of circular and elliptic cone with newlinedifferent base-jet configuration. All the experiments have been carried out in a closed jet test section newlinetable top subsonic wind tunnel. The Cross section size of the test section is newline240 mm X 180 mm with 660 mm length. The Base area and length of the newlinecones were maintained constant as 1296 mm2 and 110mm respectively to newlinemaintain constant finesse ratio of 2.75. The test section blockage ratio of the newlinetest model in the wind tunnel experiments is 0.03. Elliptic and circular cone newlinemodels are mounted symmetrically in the test section during all the newlineexperiments. Experiments were conducted in three categories as follows: i) Static newlinepressure measurement along the wake axis of the circular and elliptic cone at 6 m/s, 15 m/s and 25 m/s freestream velocity without any base-jet injection newlineusing Digital Sensor Array (DSA-Scanivalve).ii) Using Constant Temperature newlineHot-wire anemometer (CTA-DANTEC), velocity and its fluctuations were newlinemeasured along the wake axis of the cones. Effect of base-jet Injection Ratio newline(IR =0.5, 0.75, 1.0, 1.25 and 1.5), base-jet Area Ratio (AR = 0.005, 0.01 and newline0.015) and base-jet orifice shape (circular, square and hexagonal) on the mean newlinevelocity and fluctuation were studied at only 25m/s freestream velocity newline(Re=66000).%%%Appendix p.225-236, References p.237-243.