Effects of geometrical parameters on the aerodynamic characteristics of a streamlined flat box girder

摘要

AbstractThe effects of aspect ratio (B/D,width to height ratio), wind fairing angle (θ) and relative height of wind nose (H/h,handHare the distances from the wind nose to the upper and lower surfaces of the girder, respectively) on the aerodynamic characteristics of a streamlined flat box girder were systematically investigated through wind tunnel experiments. A total of 21 cases were tested withB/D?=?6, 9 and 12,θ?=?45°, 55°, 65° and 75°, andH/h?=?1, 2, 3 and 4, which covered most of the typical large span bridges in use. The Reynolds number based on the freestream oncoming velocityU∞and model heightDwas 3.3?×?104. The experimental results show that the effects ofB/D,θandH/hare negligible at small wind attack angle (α) with |α|?α| > 4°, which is associated with the states of the flow around the girder. With the increases of |α|, the flow around the girder may transfer from trailing edge vortex shedding (TEVS) to impinging leading edge vortex (ILEV) and leading edge vortex shedding (LEVS). Generally, the girder withH/h?=?2–3 and largerB/Dandθcorresponds to larger range ofαwith TEVS, which is favorable to the wind resistance stabilization of the girder.Highlights?The aerodynamic of 21 kinds of streamlined flat box girders are investigated.?Two kinds of Storuhal numbers are observed in the test.?The POD is used to reveal the induced mechanism of the two kinds of Storuhal numbers.]]>