Dynamic evaluation of the solar chimney

[摘要] Previous studies on the solar chimney have shown that its structural integrity might becompromised by the occurrence of resonance. A structure may displace excessively when a load ofthe same frequency as a structural eigen-frequency is applied. The wind gust spectrum peaks nearthe solar chimney's fundamental resonance frequency. This phenomenon poses a reliability threat,not only to the solar chimney, but also to all high-rise, slender structures.Structural dynamics describe the response of a structure to a varying load. The dynamic equationincorporates four terms that bind the factors responsible for resonance: kinetic energy, dissipatedenergy (damping), stiffness energy and input energy (loading). After a brief literature study onclassical chimney design procedures, the study scrutinises each of these terms individually in thecontext of the solar chimney as designed to date.A dynamic analysis is undertaken with all the above-mentioned parameters as defined andestimated by the study. The results from the analysis show amplifications of approximately threetimes the static displacements. In load cases where the wind direction inverts along the height,higher eigen-modes are excited. However, the most severe dynamic amplification occurs at thefundamental eigen-mode. In the context of solar chimney research, this study brings valuable newinsights regarding the dynamic behaviour of the chimney structure to the fore.

[发布机构] Stellenbosch University