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The bridge girder’s aerodynamic configuration substantially governs its aerodynamic loading and wind-induced vibration characteristics. Extensive research has been performed to optimize the configuration of girders and implement aerodynamic measures to enhance the bridge’s wind resistance. In some practical bridge engineering projects, the aerodynamic configuration of the bridge girder is asymmetric. However, studies investigating the aerodynamic properties of asymmetric girders are limited. In this paper, the aerodynamic loading and vibration characteristics of the Π-shaped girders and box girders with asymmetric bikeways are experimentally studied. Through an extensive series of wind tunnel experiments, the static wind loading coefficients, flutter derivatives, vortex-induced vibration (VIV) responses, and the critical flutter velocities are compared across varying wind direction angles (WDAs). The experimental results demonstrate that the asymmetric girder configurations have different characteristics in both the static wind loading coefficient and flutter derivative in different WDAs. The influence of WDAs on the above-mentioned aerodynamic force coefficients of the asymmetric Π-shaped girder is more pronounced than that on the asymmetric box girder. For the asymmetric Π-shaped girder, the heaving VIV responses at a 0° WDA are smaller than those at a 180° WDA, but the torsional VIV responses at a 0° WDA are larger. Experimental results for critical flutter velocities indicate that the flutter performance at a 0° WDA is better than that at a 180° WDA, especially at positive angles of attack (AOAs) for the two types of asymmetric bridge girders.

Long-span suspension bridges, due to their flexibility and lightness, are much prone to the wind loads, aerodynamics performance has become an important aspect of the design of long-span suspension bridges. In this study, the static wind load acting on the suspension bridge during erection has been investigated through wind tunnel test and numerical analysis. The wind tunnel test was performed using a 1:50 scale section model of the bridge, the static wind load acting on the section model was measured with varying attack angles. Numerical method used here was computational fluid dynamics simulation, a two-dimensional model is adopted in the first stage of the analysis, then the SIMPLE algorithm was employed to solve the governing equations. The analytical results were compared with the wind tunnel test data, it was shown from the study that the results of CFD simulation was good agreement with that of the wind tunnel test.

The effect of wind load is one of the very significant factors in building and structure design. An investigation has been carried out into the wind effect on a Pentagonal cross-section with an open circuit wind tunnel. The experiment was conducted at a constant flow velocity of 13.2 m/s and a Reynolds number of 4.22 x 104. The test was carried out on a single cylinder positioned facing across the flow direction at various angles of attack from 0° to 72° at a step of 9°. Each face of a pentagonal cylindrical model was divided into five tapping points and connected with inclined multi-manometers using copper capillary and plastic tubes to measure the surface static pressure on the cylinder surface. Pressure coefficients were calculated from the measured surface static pressure, which was then used to estimate the drag and lift coefficients. A significant drop of 0.52 in the drag coefficient values has been observed for the single pentagonal cylinder in comparison to that of the single square cylinder. The overall lift coefficient values of the single pentagonal cylinder are found to be lower than that of a single square cylinder except at 9 0 . The fluctuation of the lift coefficient curve has a 9 0 phase shift than that of the square cylinder; however, the pattern of their variations has shown a similar trend except for the angle of attack of 0 0 . The stagnation point was identified on the front face of the pentagonal cylinder. These findings will assist engineers and architects in designing much safer buildings.

This paper presents the experimental studies of the efficiency of open and ducted contra-rotating propeller systems operating in the low Reynolds number range. Eight off-the-shelf propellers were selected with a diameter in the range from 139 mm to 377 mm and seven ducts were built with the duct length of 0.28–0.53 the propeller diameter. Static and wind tunnel experiments were conducted. The maximum increase in the static thrust coefficient and power loading for the ducted contra-rotating propeller systems over the open systems was found to be 25% and 50%, respectively. This performance improvement for the medium size ducted systems is smaller than that observed in previous studies for ducts longer than the 0.8 propeller diameter but greater than for ducts shorter than the 0.15 propeller diameter. The thrust coefficient decreases with an advance ratio increase. The power loading of both open and ducted systems drops dramatically after reaching maxima.