Investigating the Prospect of Rooftop Flapping Wind Turbine in Bangladesh

The objective of this research is mainly focused on environment-friendly and moderately slow flapping wind turbine which can easily operate in or near urban areas or rooftops owing to scale merit with low-frequency turbine noise, installation cost, avian mortality rate and safety consideration etc. We considered lift and drag based slow flapping type wind turbine to operate in the residential arena. In order to study the flapping wind turbine performance, we collect ten years of wind velocity records from the Bangladesh Meteorological Department for two different stations in Bangladesh. The velocity contours and profiles have been the points of observation to find out the suitable turbine shape having the efficiency to initiate the turbine rotation. We made a simple comparative study of the wind velocities profile obtained from the different stations in Bangladesh. A simple numerical study has been conducted and presented by graphical analysis to inspect the wind flow above the constructed structure. Finally, we analyze the wind velocity for the individual months and determine the turbine performance in terms of torque for the average wind velocities of Dhaka and Cox’s Bazar stations.

Effects of non-stationary wind velocity models on buffeting performance of closed-box girder suspension bridges

Non-stationary characteristic in nature wind has a great effect on buffeting performance of long-span bridges.The influence of key parameters in non-stationary wind velocity models on nonlinear buffeting responses of a super long-span suspension bridge was investigated in this paper.Firstly,four non-stationary wind velocity models are established by combing the time-varying average wind velocity with an exponential function and the fluctuating wind velocity with four modulation functions,respectively.These non-stationary wind velocity models have obvious non-stationary characteristics and then are validated by the classical power spectrum densities.Finally,three displacement responses of the bridge deck under four different independent variables ofβin the exponential function and four modulation functions were compared,respectively.Results show that the turbulence intensities using two non-uniform modulation functions(NMF)are larger than those using uniform modulation functions(uMF).Moreover,the root mean square(RMS)values of three displacement responses increase with the decrease ofβ.Besides,the RMS values of three displacement under two NMFs are larger than those under two uMFs,and their RMS values under the second uMF are the smallest.